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help / color / mirror / Atom feedFrom: Tomas Vondra <[email protected]>
Subject: [PATCH 3/3] Extended statistics on expressions
Date: Thu, 3 Dec 2020 16:19:58 +0100
Allow defining extended statistics on expressions, not just simple
column references. With this commit, it's possible to do things like
CREATE TABLE t (a int);
CREATE STATISTICS s ON mod(a,10), mod(a,20) FROM t;
and the collected statistics will be useful for estimating queries
using those expressions in various places, like
SELECT * FROM t WHERE mod(a,10) = 0 AND mod(a,20) = 0;
or
SELECT mod(a,10), mod(a,20) FROM t GROUP BY 1, 2;
The commit also adds a new statistics type "expressions" which builds
the usual per-column statistics for each expression, allowing better
estimates even for queries with just a single expression, which are
not affected by multi-column statistics. This achieves the same goal
as creating expression indexes, without index maintenance overhead.
---
doc/src/sgml/catalogs.sgml | 238 ++-
doc/src/sgml/ref/create_statistics.sgml | 107 +-
src/backend/catalog/Makefile | 8 +-
src/backend/catalog/system_views.sql | 74 +
src/backend/commands/statscmds.c | 319 +++-
src/backend/nodes/copyfuncs.c | 14 +
src/backend/nodes/equalfuncs.c | 13 +
src/backend/nodes/outfuncs.c | 12 +
src/backend/optimizer/util/plancat.c | 62 +
src/backend/parser/gram.y | 38 +-
src/backend/parser/parse_agg.c | 10 +
src/backend/parser/parse_expr.c | 6 +
src/backend/parser/parse_func.c | 3 +
src/backend/parser/parse_utilcmd.c | 121 +-
src/backend/statistics/dependencies.c | 369 +++-
src/backend/statistics/extended_stats.c | 1559 ++++++++++++++++-
src/backend/statistics/mcv.c | 295 +++-
src/backend/statistics/mvdistinct.c | 101 +-
src/backend/tcop/utility.c | 23 +-
src/backend/utils/adt/ruleutils.c | 269 ++-
src/backend/utils/adt/selfuncs.c | 408 ++++-
src/bin/pg_dump/t/002_pg_dump.pl | 12 +
src/bin/psql/describe.c | 66 +-
src/include/catalog/pg_proc.dat | 8 +
src/include/catalog/pg_statistic_ext.h | 4 +
src/include/catalog/pg_statistic_ext_data.h | 1 +
src/include/nodes/nodes.h | 1 +
src/include/nodes/parsenodes.h | 16 +
src/include/nodes/pathnodes.h | 3 +-
src/include/parser/parse_node.h | 1 +
src/include/parser/parse_utilcmd.h | 2 +
.../statistics/extended_stats_internal.h | 40 +-
src/include/statistics/statistics.h | 2 +
.../regress/expected/create_table_like.out | 20 +-
src/test/regress/expected/rules.out | 75 +
src/test/regress/expected/stats_ext.out | 681 ++++++-
src/test/regress/sql/create_table_like.sql | 2 +
src/test/regress/sql/stats_ext.sql | 313 +++-
38 files changed, 4926 insertions(+), 370 deletions(-)
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 43d7a1ad90..eef546a23f 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -7347,7 +7347,7 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l
<structfield>stxkind</structfield> <type>char[]</type>
</para>
<para>
- An array containing codes for the enabled statistic kinds;
+ An array containing codes for the enabled statistics kinds;
valid values are:
<literal>d</literal> for n-distinct statistics,
<literal>f</literal> for functional dependency statistics, and
@@ -9396,6 +9396,11 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l
<entry>extended planner statistics</entry>
</row>
+ <row>
+ <entry><link linkend="view-pg-stats-ext-exprs"><structname>pg_stats_ext_exprs</structname></link></entry>
+ <entry>extended planner statistics for expressions</entry>
+ </row>
+
<row>
<entry><link linkend="view-pg-tables"><structname>pg_tables</structname></link></entry>
<entry>tables</entry>
@@ -12958,6 +12963,237 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
</sect1>
+ <sect1 id="view-pg-stats-ext-exprs">
+ <title><structname>pg_stats_ext_exprs</structname></title>
+
+ <indexterm zone="view-pg-stats-ext-exprs">
+ <primary>pg_stats_ext_exprs</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_stats_ext_exprs</structname> provides access to
+ the information stored in the <link
+ linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>
+ and <link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>
+ catalogs. This view allows access only to rows of
+ <link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link> and <link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>
+ that correspond to tables the user has permission to read, and therefore
+ it is safe to allow public read access to this view.
+ </para>
+
+ <para>
+ <structname>pg_stats_ext_exprs</structname> is also designed to present
+ the information in a more readable format than the underlying catalogs
+ — at the cost that its schema must be extended whenever the structure
+ of statistics in <link linkend="catalog-pg-statistic"><structname>pg_statistic</structname></link> changes.
+ </para>
+
+ <table>
+ <title><structname>pg_stats_ext_exprs</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>schemaname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
+ </para>
+ <para>
+ Name of schema containing table
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>tablename</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>relname</structfield>)
+ </para>
+ <para>
+ Name of table
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>statistics_schemaname</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.<structfield>nspname</structfield>)
+ </para>
+ <para>
+ Name of schema containing extended statistic
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>statistics_name</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>.<structfield>stxname</structfield>)
+ </para>
+ <para>
+ Name of extended statistics
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>statistics_owner</structfield> <type>name</type>
+ (references <link linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.<structfield>rolname</structfield>)
+ </para>
+ <para>
+ Owner of the extended statistics
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>expr</structfield> <type>text</type>
+ </para>
+ <para>
+ Expression the extended statistics is defined on
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>null_frac</structfield> <type>float4</type>
+ </para>
+ <para>
+ Fraction of column entries that are null
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>avg_width</structfield> <type>int4</type>
+ </para>
+ <para>
+ Average width in bytes of column's entries
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>n_distinct</structfield> <type>float4</type>
+ </para>
+ <para>
+ If greater than zero, the estimated number of distinct values in the
+ column. If less than zero, the negative of the number of distinct
+ values divided by the number of rows. (The negated form is used when
+ <command>ANALYZE</command> believes that the number of distinct values is
+ likely to increase as the table grows; the positive form is used when
+ the column seems to have a fixed number of possible values.) For
+ example, -1 indicates a unique column in which the number of distinct
+ values is the same as the number of rows.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_vals</structfield> <type>anyarray</type>
+ </para>
+ <para>
+ A list of the most common values in the column. (Null if
+ no values seem to be more common than any others.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_freqs</structfield> <type>float4[]</type>
+ </para>
+ <para>
+ A list of the frequencies of the most common values,
+ i.e., number of occurrences of each divided by total number of rows.
+ (Null when <structfield>most_common_vals</structfield> is.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>histogram_bounds</structfield> <type>anyarray</type>
+ </para>
+ <para>
+ A list of values that divide the column's values into groups of
+ approximately equal population. The values in
+ <structfield>most_common_vals</structfield>, if present, are omitted from this
+ histogram calculation. (This column is null if the column data type
+ does not have a <literal><</literal> operator or if the
+ <structfield>most_common_vals</structfield> list accounts for the entire
+ population.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>correlation</structfield> <type>float4</type>
+ </para>
+ <para>
+ Statistical correlation between physical row ordering and
+ logical ordering of the column values. This ranges from -1 to +1.
+ When the value is near -1 or +1, an index scan on the column will
+ be estimated to be cheaper than when it is near zero, due to reduction
+ of random access to the disk. (This column is null if the column data
+ type does not have a <literal><</literal> operator.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_elems</structfield> <type>anyarray</type>
+ </para>
+ <para>
+ A list of non-null element values most often appearing within values of
+ the column. (Null for scalar types.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>most_common_elem_freqs</structfield> <type>float4[]</type>
+ </para>
+ <para>
+ A list of the frequencies of the most common element values, i.e., the
+ fraction of rows containing at least one instance of the given value.
+ Two or three additional values follow the per-element frequencies;
+ these are the minimum and maximum of the preceding per-element
+ frequencies, and optionally the frequency of null elements.
+ (Null when <structfield>most_common_elems</structfield> is.)
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>elem_count_histogram</structfield> <type>float4[]</type>
+ </para>
+ <para>
+ A histogram of the counts of distinct non-null element values within the
+ values of the column, followed by the average number of distinct
+ non-null elements. (Null for scalar types.)
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ The maximum number of entries in the array fields can be controlled on a
+ column-by-column basis using the <link linkend="sql-altertable"><command>ALTER
+ TABLE SET STATISTICS</command></link>
+ command, or globally by setting the
+ <xref linkend="guc-default-statistics-target"/> run-time parameter.
+ </para>
+
+ </sect1>
+
<sect1 id="view-pg-tables">
<title><structname>pg_tables</structname></title>
diff --git a/doc/src/sgml/ref/create_statistics.sgml b/doc/src/sgml/ref/create_statistics.sgml
index 4363be50c3..266aefaee0 100644
--- a/doc/src/sgml/ref/create_statistics.sgml
+++ b/doc/src/sgml/ref/create_statistics.sgml
@@ -21,9 +21,13 @@ PostgreSQL documentation
<refsynopsisdiv>
<synopsis>
+CREATE STATISTICS [ IF NOT EXISTS ] <replaceable class="parameter">statistics_name</replaceable>
+ ON ( <replaceable class="parameter">expression</replaceable> )
+ FROM <replaceable class="parameter">table_name</replaceable>
+
CREATE STATISTICS [ IF NOT EXISTS ] <replaceable class="parameter">statistics_name</replaceable>
[ ( <replaceable class="parameter">statistics_kind</replaceable> [, ... ] ) ]
- ON <replaceable class="parameter">column_name</replaceable>, <replaceable class="parameter">column_name</replaceable> [, ...]
+ ON { <replaceable class="parameter">column_name</replaceable> | ( <replaceable class="parameter">expression</replaceable> ) } [, ...]
FROM <replaceable class="parameter">table_name</replaceable>
</synopsis>
@@ -39,6 +43,16 @@ CREATE STATISTICS [ IF NOT EXISTS ] <replaceable class="parameter">statistics_na
database and will be owned by the user issuing the command.
</para>
+ <para>
+ The <command>CREATE STATISTICS</command> command has two basic forms. The
+ simple variant allows to build statistics for a single expression, does
+ not allow specifying any statistics kinds and provides benefits similar
+ to an expression index. The full variant allows defining statistics objects
+ on multiple columns and expressions, and selecting which statistics kinds will
+ be built. The per-expression statistics are built automatically when there
+ is at least one expression.
+ </para>
+
<para>
If a schema name is given (for example, <literal>CREATE STATISTICS
myschema.mystat ...</literal>) then the statistics object is created in the
@@ -86,7 +100,9 @@ CREATE STATISTICS [ IF NOT EXISTS ] <replaceable class="parameter">statistics_na
dependency statistics, and <literal>mcv</literal> which enables
most-common values lists.
If this clause is omitted, all supported statistics kinds are
- included in the statistics object.
+ included in the statistics object. Expression statistics are included
+ automatically when the statistics definition includes complex
+ expressions and not just simple column references.
For more information, see <xref linkend="planner-stats-extended"/>
and <xref linkend="multivariate-statistics-examples"/>.
</para>
@@ -104,6 +120,17 @@ CREATE STATISTICS [ IF NOT EXISTS ] <replaceable class="parameter">statistics_na
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><replaceable class="parameter">expression</replaceable></term>
+ <listitem>
+ <para>
+ The expression to be covered by the computed statistics. In this case
+ only a single expression is required, in which case only the expression
+ statistics kind is allowed. The order of expressions is insignificant.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry>
<term><replaceable class="parameter">table_name</replaceable></term>
<listitem>
@@ -125,6 +152,22 @@ CREATE STATISTICS [ IF NOT EXISTS ] <replaceable class="parameter">statistics_na
reading it. Once created, however, the ownership of the statistics
object is independent of the underlying table(s).
</para>
+
+ <para>
+ Creating expression statistics is allowed only when expressions are given.
+ Expression statistics are per-expression and are similar to creating an
+ index on the expression, except that they avoid the overhead of the index.
+ </para>
+
+ <para>
+ All functions and operators used in a statistics definition must be
+ <quote>immutable</quote>, that is, their results must depend only on
+ their arguments and never on any outside influence (such as
+ the contents of another table or the current time). This restriction
+ ensures that the behavior of the statistics is well-defined. To use a
+ user-defined function in a statistics expression, remember to mark
+ the function immutable when you create it.
+ </para>
</refsect1>
<refsect1 id="sql-createstatistics-examples">
@@ -196,6 +239,66 @@ EXPLAIN ANALYZE SELECT * FROM t2 WHERE (a = 1) AND (b = 2);
in the table, allowing it to generate better estimates in both cases.
</para>
+ <para>
+ Create table <structname>t3</structname> with a single timestamp column,
+ and run a query using an expression on that column. Without extended
+ statistics, the planner has no information about data distribution for
+ results of those expression, and uses default estimates as illustrated
+ by the first query. The planner also does not realize the value of the
+ second column fully defines the value of the other column, because date
+ truncated to day still identifies the month. Then expression and
+ ndistinct statistics are built on those two columns:
+
+<programlisting>
+CREATE TABLE t3 (
+ a timestamp
+);
+
+INSERT INTO t3 SELECT i FROM generate_series('2020-01-01'::timestamp,
+ '2020-12-31'::timestamp,
+ '1 minute'::interval) s(i);
+
+ANALYZE t3;
+
+-- the number of matching rows will be drastically underestimated:
+EXPLAIN ANALYZE SELECT * FROM t3
+ WHERE date_trunc('month', a) = '2020-01-01'::timestamp;
+
+EXPLAIN ANALYZE SELECT * FROM t3
+ WHERE date_trunc('day', a) BETWEEN '2020-01-01'::timestamp
+ AND '2020-06-30'::timestamp;
+
+EXPLAIN ANALYZE SELECT date_trunc('month', a), date_trunc('day', a)
+ FROM t3 GROUP BY 1, 2;
+
+-- per-expression statistics are built automatically
+CREATE STATISTICS s3 (ndistinct) ON date_trunc('month', a), date_trunc('day', a) FROM t3;
+
+ANALYZE t1;
+
+-- now the row count estimates are more accurate:
+EXPLAIN ANALYZE SELECT * FROM t3
+ WHERE date_trunc('month', a) = '2020-01-01'::timestamp;
+
+EXPLAIN ANALYZE SELECT * FROM t3
+ WHERE date_trunc('day', a) BETWEEN '2020-01-01'::timestamp
+ AND '2020-06-30'::timestamp;
+
+EXPLAIN ANALYZE SELECT date_trunc('month', a), date_trunc('day', a)
+ FROM t3 GROUP BY 1, 2;
+</programlisting>
+
+ Without expression and ndistinct statistics, the planner would assume
+ that the two <literal>WHERE</literal> and <literal>GROUP BY</literal>
+ conditions are independent, and would multiply their selectivities
+ together to arrive at a much-too-small row count estimate in the first
+ two queries, and a much-too-high group count estimate in the aggregate
+ query. This is further exacerbated by the lack of accurate statistics
+ for the expressions, forcing the planner to use default selectivities.
+ With such statistics, the planner recognizes that the conditions are
+ correlated and arrives at much more accurate estimates.
+ </para>
+
</refsect1>
<refsect1>
diff --git a/src/backend/catalog/Makefile b/src/backend/catalog/Makefile
index c85f0ca7b6..fa91ff1c42 100644
--- a/src/backend/catalog/Makefile
+++ b/src/backend/catalog/Makefile
@@ -49,15 +49,15 @@ include $(top_srcdir)/src/backend/common.mk
# Note: the order of this list determines the order in which the catalog
# header files are assembled into postgres.bki. BKI_BOOTSTRAP catalogs
-# must appear first, and there are reputedly other, undocumented ordering
-# dependencies.
+# must appear first, and pg_statistic before pg_statistic_ext_data, and
+# there are reputedly other, undocumented ordering dependencies.
CATALOG_HEADERS := \
pg_proc.h pg_type.h pg_attribute.h pg_class.h \
pg_attrdef.h pg_constraint.h pg_inherits.h pg_index.h pg_operator.h \
pg_opfamily.h pg_opclass.h pg_am.h pg_amop.h pg_amproc.h \
pg_language.h pg_largeobject_metadata.h pg_largeobject.h pg_aggregate.h \
- pg_statistic_ext.h pg_statistic_ext_data.h \
- pg_statistic.h pg_rewrite.h pg_trigger.h pg_event_trigger.h pg_description.h \
+ pg_statistic.h pg_statistic_ext.h pg_statistic_ext_data.h \
+ pg_rewrite.h pg_trigger.h pg_event_trigger.h pg_description.h \
pg_cast.h pg_enum.h pg_namespace.h pg_conversion.h pg_depend.h \
pg_database.h pg_db_role_setting.h pg_tablespace.h \
pg_authid.h pg_auth_members.h pg_shdepend.h pg_shdescription.h \
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index 5d89e77dbe..bd2a7c2ac2 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -264,6 +264,7 @@ CREATE VIEW pg_stats_ext WITH (security_barrier) AS
JOIN pg_attribute a
ON (a.attrelid = s.stxrelid AND a.attnum = k)
) AS attnames,
+ pg_get_statisticsobjdef_expressions(s.oid) as exprs,
s.stxkind AS kinds,
sd.stxdndistinct AS n_distinct,
sd.stxddependencies AS dependencies,
@@ -290,6 +291,79 @@ CREATE VIEW pg_stats_ext WITH (security_barrier) AS
WHERE NOT has_column_privilege(c.oid, a.attnum, 'select') )
AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+CREATE VIEW pg_stats_ext_exprs WITH (security_barrier) AS
+ SELECT cn.nspname AS schemaname,
+ c.relname AS tablename,
+ sn.nspname AS statistics_schemaname,
+ s.stxname AS statistics_name,
+ pg_get_userbyid(s.stxowner) AS statistics_owner,
+ stat.expr,
+ (stat.a).stanullfrac AS null_frac,
+ (stat.a).stawidth AS avg_width,
+ (stat.a).stadistinct AS n_distinct,
+ (CASE
+ WHEN (stat.a).stakind1 = 1 THEN (stat.a).stavalues1
+ WHEN (stat.a).stakind2 = 1 THEN (stat.a).stavalues2
+ WHEN (stat.a).stakind3 = 1 THEN (stat.a).stavalues3
+ WHEN (stat.a).stakind4 = 1 THEN (stat.a).stavalues4
+ WHEN (stat.a).stakind5 = 1 THEN (stat.a).stavalues5
+ END) AS most_common_vals,
+ (CASE
+ WHEN (stat.a).stakind1 = 1 THEN (stat.a).stanumbers1
+ WHEN (stat.a).stakind2 = 1 THEN (stat.a).stanumbers2
+ WHEN (stat.a).stakind3 = 1 THEN (stat.a).stanumbers3
+ WHEN (stat.a).stakind4 = 1 THEN (stat.a).stanumbers4
+ WHEN (stat.a).stakind5 = 1 THEN (stat.a).stanumbers5
+ END) AS most_common_freqs,
+ (CASE
+ WHEN (stat.a).stakind1 = 2 THEN (stat.a).stavalues1
+ WHEN (stat.a).stakind2 = 2 THEN (stat.a).stavalues2
+ WHEN (stat.a).stakind3 = 2 THEN (stat.a).stavalues3
+ WHEN (stat.a).stakind4 = 2 THEN (stat.a).stavalues4
+ WHEN (stat.a).stakind5 = 2 THEN (stat.a).stavalues5
+ END) AS histogram_bounds,
+ (CASE
+ WHEN (stat.a).stakind1 = 3 THEN (stat.a).stanumbers1[1]
+ WHEN (stat.a).stakind2 = 3 THEN (stat.a).stanumbers2[1]
+ WHEN (stat.a).stakind3 = 3 THEN (stat.a).stanumbers3[1]
+ WHEN (stat.a).stakind4 = 3 THEN (stat.a).stanumbers4[1]
+ WHEN (stat.a).stakind5 = 3 THEN (stat.a).stanumbers5[1]
+ END) correlation,
+ (CASE
+ WHEN (stat.a).stakind1 = 4 THEN (stat.a).stavalues1
+ WHEN (stat.a).stakind2 = 4 THEN (stat.a).stavalues2
+ WHEN (stat.a).stakind3 = 4 THEN (stat.a).stavalues3
+ WHEN (stat.a).stakind4 = 4 THEN (stat.a).stavalues4
+ WHEN (stat.a).stakind5 = 4 THEN (stat.a).stavalues5
+ END) AS most_common_elems,
+ (CASE
+ WHEN (stat.a).stakind1 = 4 THEN (stat.a).stanumbers1
+ WHEN (stat.a).stakind2 = 4 THEN (stat.a).stanumbers2
+ WHEN (stat.a).stakind3 = 4 THEN (stat.a).stanumbers3
+ WHEN (stat.a).stakind4 = 4 THEN (stat.a).stanumbers4
+ WHEN (stat.a).stakind5 = 4 THEN (stat.a).stanumbers5
+ END) AS most_common_elem_freqs,
+ (CASE
+ WHEN (stat.a).stakind1 = 5 THEN (stat.a).stanumbers1
+ WHEN (stat.a).stakind2 = 5 THEN (stat.a).stanumbers2
+ WHEN (stat.a).stakind3 = 5 THEN (stat.a).stanumbers3
+ WHEN (stat.a).stakind4 = 5 THEN (stat.a).stanumbers4
+ WHEN (stat.a).stakind5 = 5 THEN (stat.a).stanumbers5
+ END) AS elem_count_histogram
+ FROM pg_statistic_ext s JOIN pg_class c ON (c.oid = s.stxrelid)
+ JOIN pg_statistic_ext_data sd ON (s.oid = sd.stxoid)
+ LEFT JOIN pg_namespace cn ON (cn.oid = c.relnamespace)
+ LEFT JOIN pg_namespace sn ON (sn.oid = s.stxnamespace)
+ LEFT JOIN LATERAL (
+ SELECT
+ *
+ FROM (
+ SELECT
+ unnest(pg_get_statisticsobjdef_expressions(s.oid)) AS expr,
+ unnest(sd.stxdexpr)::pg_statistic AS a
+ ) x
+ ) stat ON sd.stxdexpr IS NOT NULL;
+
-- unprivileged users may read pg_statistic_ext but not pg_statistic_ext_data
REVOKE ALL on pg_statistic_ext_data FROM public;
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index 2bae205845..7370af820f 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -29,6 +29,8 @@
#include "commands/comment.h"
#include "commands/defrem.h"
#include "miscadmin.h"
+#include "nodes/nodeFuncs.h"
+#include "optimizer/optimizer.h"
#include "statistics/statistics.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
@@ -62,7 +64,8 @@ ObjectAddress
CreateStatistics(CreateStatsStmt *stmt)
{
int16 attnums[STATS_MAX_DIMENSIONS];
- int numcols = 0;
+ int nattnums = 0;
+ int numcols;
char *namestr;
NameData stxname;
Oid statoid;
@@ -74,21 +77,25 @@ CreateStatistics(CreateStatsStmt *stmt)
Datum datavalues[Natts_pg_statistic_ext_data];
bool datanulls[Natts_pg_statistic_ext_data];
int2vector *stxkeys;
+ List *stxexprs = NIL;
+ Datum exprsDatum;
Relation statrel;
Relation datarel;
Relation rel = NULL;
Oid relid;
ObjectAddress parentobject,
myself;
- Datum types[3]; /* one for each possible type of statistic */
+ Datum types[4]; /* one for each possible type of statistic */
int ntypes;
ArrayType *stxkind;
bool build_ndistinct;
bool build_dependencies;
bool build_mcv;
+ bool build_expressions;
bool requested_type = false;
int i;
ListCell *cell;
+ ListCell *cell2;
Assert(IsA(stmt, CreateStatsStmt));
@@ -190,72 +197,169 @@ CreateStatistics(CreateStatsStmt *stmt)
}
/*
- * Currently, we only allow simple column references in the expression
- * list. That will change someday, and again the grammar already supports
- * it so we have to enforce restrictions here. For now, we can convert
- * the expression list to a simple array of attnums. While at it, enforce
- * some constraints.
+ * Make sure no more than STATS_MAX_DIMENSIONS columns are used. There
+ * might be duplicates and so on, but we'll deal with those later.
+ */
+ numcols = list_length(stmt->exprs);
+ if (numcols > STATS_MAX_DIMENSIONS)
+ ereport(ERROR,
+ (errcode(ERRCODE_TOO_MANY_COLUMNS),
+ errmsg("cannot have more than %d columns in statistics",
+ STATS_MAX_DIMENSIONS)));
+
+ /*
+ * Convert the expression list to a simple array of attnums, but also
+ * keep a list of more complex expressions. While at it, enforce some
+ * constraints.
*/
foreach(cell, stmt->exprs)
{
Node *expr = (Node *) lfirst(cell);
- ColumnRef *cref;
- char *attname;
+ StatsElem *selem;
HeapTuple atttuple;
Form_pg_attribute attForm;
TypeCacheEntry *type;
- if (!IsA(expr, ColumnRef))
+ /*
+ * XXX How could we get anything else than a StatsElem, given the
+ * grammar? But let's keep it as a safety, maybe shall we turn it
+ * into an assert?
+ */
+ if (!IsA(expr, StatsElem))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("only simple column references are allowed in CREATE STATISTICS")));
- cref = (ColumnRef *) expr;
+ errmsg("only simple column references and expressions are allowed in CREATE STATISTICS")));
- if (list_length(cref->fields) != 1)
- ereport(ERROR,
- (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("only simple column references are allowed in CREATE STATISTICS")));
- attname = strVal((Value *) linitial(cref->fields));
+ selem = (StatsElem *) expr;
- atttuple = SearchSysCacheAttName(relid, attname);
- if (!HeapTupleIsValid(atttuple))
- ereport(ERROR,
- (errcode(ERRCODE_UNDEFINED_COLUMN),
- errmsg("column \"%s\" does not exist",
- attname)));
- attForm = (Form_pg_attribute) GETSTRUCT(atttuple);
+ if (selem->name) /* column reference */
+ {
+ char *attname;
+ attname = selem->name;
+
+ atttuple = SearchSysCacheAttName(relid, attname);
+ if (!HeapTupleIsValid(atttuple))
+ ereport(ERROR,
+ (errcode(ERRCODE_UNDEFINED_COLUMN),
+ errmsg("column \"%s\" does not exist",
+ attname)));
+ attForm = (Form_pg_attribute) GETSTRUCT(atttuple);
+
+ /* Disallow use of system attributes in extended stats */
+ if (attForm->attnum <= 0)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("statistics creation on system columns is not supported")));
+
+ /* Disallow data types without a less-than operator */
+ type = lookup_type_cache(attForm->atttypid, TYPECACHE_LT_OPR);
+ if (type->lt_opr == InvalidOid)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("column \"%s\" cannot be used in statistics because its type %s has no default btree operator class",
+ attname, format_type_be(attForm->atttypid))));
+
+ attnums[nattnums] = attForm->attnum;
+ nattnums++;
+ ReleaseSysCache(atttuple);
+ }
+ else /* expression */
+ {
+ Node *expr = selem->expr;
+ Oid atttype;
+
+ Assert(expr != NULL);
+
+ /*
+ * Disallow data types without a less-than operator.
+ *
+ * We ignore this for statistics on a single expression, in
+ * which case we'll build the regular statistics only (and
+ * that code can deal with such data types).
+ */
+ if (list_length(stmt->exprs) > 1)
+ {
+ atttype = exprType(expr);
+ type = lookup_type_cache(atttype, TYPECACHE_LT_OPR);
+ if (type->lt_opr == InvalidOid)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("expression cannot be used in statistics because its type %s has no default btree operator class",
+ format_type_be(atttype))));
+ }
+
+ stxexprs = lappend(stxexprs, expr);
+ }
+ }
- /* Disallow use of system attributes in extended stats */
- if (attForm->attnum <= 0)
+ /*
+ * Parse the statistics kinds. Firstly, check that this is not the
+ * variant building statistics for a single expression, in which case
+ * we don't allow specifying any statistics kinds. The simple variant
+ * only has one expression, and does not allow statistics kinds.
+ */
+ if ((list_length(stmt->exprs) == 1) && (list_length(stxexprs) == 1))
+ {
+ /* statistics kinds not specified */
+ if (list_length(stmt->stat_types) > 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("statistics creation on system columns is not supported")));
+ errmsg("when building statistics on a single expression, statistics kinds may not be specified")));
+ }
- /* Disallow data types without a less-than operator */
- type = lookup_type_cache(attForm->atttypid, TYPECACHE_LT_OPR);
- if (type->lt_opr == InvalidOid)
- ereport(ERROR,
- (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("column \"%s\" cannot be used in statistics because its type %s has no default btree operator class",
- attname, format_type_be(attForm->atttypid))));
+ /* OK, let's check that we recognize the statistics kinds. */
+ build_ndistinct = false;
+ build_dependencies = false;
+ build_mcv = false;
+ foreach(cell, stmt->stat_types)
+ {
+ char *type = strVal((Value *) lfirst(cell));
- /* Make sure no more than STATS_MAX_DIMENSIONS columns are used */
- if (numcols >= STATS_MAX_DIMENSIONS)
+ if (strcmp(type, "ndistinct") == 0)
+ {
+ build_ndistinct = true;
+ requested_type = true;
+ }
+ else if (strcmp(type, "dependencies") == 0)
+ {
+ build_dependencies = true;
+ requested_type = true;
+ }
+ else if (strcmp(type, "mcv") == 0)
+ {
+ build_mcv = true;
+ requested_type = true;
+ }
+ else
ereport(ERROR,
- (errcode(ERRCODE_TOO_MANY_COLUMNS),
- errmsg("cannot have more than %d columns in statistics",
- STATS_MAX_DIMENSIONS)));
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("unrecognized statistics kind \"%s\"",
+ type)));
+ }
- attnums[numcols] = attForm->attnum;
- numcols++;
- ReleaseSysCache(atttuple);
+ /*
+ * If no statistic type was specified, build them all (but request
+ * expression stats only when there actually are any expressions).
+ */
+ if (!requested_type)
+ {
+ build_ndistinct = (numcols >= 2);
+ build_dependencies = (numcols >= 2);
+ build_mcv = (numcols >= 2);
}
/*
- * Check that at least two columns were specified in the statement. The
- * upper bound was already checked in the loop above.
+ * When there are non-trivial expressions, build the expression stats
+ * automatically. This allows calculating good estimates for stats that
+ * consider per-clause estimates (e.g. functional dependencies).
+ */
+ build_expressions = (list_length(stxexprs) > 0);
+
+ /*
+ * Check that at least two columns were specified in the statement, or
+ * that we're building statistics on a single expression.
*/
- if (numcols < 2)
+ if ((numcols < 2) && (list_length(stxexprs) != 1))
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("extended statistics require at least 2 columns")));
@@ -265,13 +369,13 @@ CreateStatistics(CreateStatsStmt *stmt)
* it does not hurt (it does not affect the efficiency, unlike for
* indexes, for example).
*/
- qsort(attnums, numcols, sizeof(int16), compare_int16);
+ qsort(attnums, nattnums, sizeof(int16), compare_int16);
/*
* Check for duplicates in the list of columns. The attnums are sorted so
* just check consecutive elements.
*/
- for (i = 1; i < numcols; i++)
+ for (i = 1; i < nattnums; i++)
{
if (attnums[i] == attnums[i - 1])
ereport(ERROR,
@@ -279,48 +383,36 @@ CreateStatistics(CreateStatsStmt *stmt)
errmsg("duplicate column name in statistics definition")));
}
- /* Form an int2vector representation of the sorted column list */
- stxkeys = buildint2vector(attnums, numcols);
-
/*
- * Parse the statistics kinds.
+ * Check for duplicate expressions. We do two loops, counting the
+ * occurrences of each expression. This is O(N^2) but we only allow
+ * small number of expressions and it's not executed often.
*/
- build_ndistinct = false;
- build_dependencies = false;
- build_mcv = false;
- foreach(cell, stmt->stat_types)
+ foreach (cell, stxexprs)
{
- char *type = strVal((Value *) lfirst(cell));
+ Node *expr1 = (Node *) lfirst(cell);
+ int cnt = 0;
- if (strcmp(type, "ndistinct") == 0)
- {
- build_ndistinct = true;
- requested_type = true;
- }
- else if (strcmp(type, "dependencies") == 0)
+ foreach (cell2, stxexprs)
{
- build_dependencies = true;
- requested_type = true;
- }
- else if (strcmp(type, "mcv") == 0)
- {
- build_mcv = true;
- requested_type = true;
+ Node *expr2 = (Node *) lfirst(cell2);
+
+ if (equal(expr1, expr2))
+ cnt += 1;
}
- else
+
+ /* every expression should find at least itself */
+ Assert(cnt >= 1);
+
+ if (cnt > 1)
ereport(ERROR,
- (errcode(ERRCODE_SYNTAX_ERROR),
- errmsg("unrecognized statistics kind \"%s\"",
- type)));
- }
- /* If no statistic type was specified, build them all. */
- if (!requested_type)
- {
- build_ndistinct = true;
- build_dependencies = true;
- build_mcv = true;
+ (errcode(ERRCODE_DUPLICATE_COLUMN),
+ errmsg("duplicate expression in statistics definition")));
}
+ /* Form an int2vector representation of the sorted column list */
+ stxkeys = buildint2vector(attnums, nattnums);
+
/* construct the char array of enabled statistic types */
ntypes = 0;
if (build_ndistinct)
@@ -329,9 +421,23 @@ CreateStatistics(CreateStatsStmt *stmt)
types[ntypes++] = CharGetDatum(STATS_EXT_DEPENDENCIES);
if (build_mcv)
types[ntypes++] = CharGetDatum(STATS_EXT_MCV);
+ if (build_expressions)
+ types[ntypes++] = CharGetDatum(STATS_EXT_EXPRESSIONS);
Assert(ntypes > 0 && ntypes <= lengthof(types));
stxkind = construct_array(types, ntypes, CHAROID, 1, true, TYPALIGN_CHAR);
+ /* convert the expressions (if any) to a text datum */
+ if (stxexprs != NIL)
+ {
+ char *exprsString;
+
+ exprsString = nodeToString(stxexprs);
+ exprsDatum = CStringGetTextDatum(exprsString);
+ pfree(exprsString);
+ }
+ else
+ exprsDatum = (Datum) 0;
+
statrel = table_open(StatisticExtRelationId, RowExclusiveLock);
/*
@@ -351,6 +457,10 @@ CreateStatistics(CreateStatsStmt *stmt)
values[Anum_pg_statistic_ext_stxkeys - 1] = PointerGetDatum(stxkeys);
values[Anum_pg_statistic_ext_stxkind - 1] = PointerGetDatum(stxkind);
+ values[Anum_pg_statistic_ext_stxexprs - 1] = exprsDatum;
+ if (exprsDatum == (Datum) 0)
+ nulls[Anum_pg_statistic_ext_stxexprs - 1] = true;
+
/* insert it into pg_statistic_ext */
htup = heap_form_tuple(statrel->rd_att, values, nulls);
CatalogTupleInsert(statrel, htup);
@@ -373,6 +483,7 @@ CreateStatistics(CreateStatsStmt *stmt)
datanulls[Anum_pg_statistic_ext_data_stxdndistinct - 1] = true;
datanulls[Anum_pg_statistic_ext_data_stxddependencies - 1] = true;
datanulls[Anum_pg_statistic_ext_data_stxdmcv - 1] = true;
+ datanulls[Anum_pg_statistic_ext_data_stxdexpr - 1] = true;
/* insert it into pg_statistic_ext_data */
htup = heap_form_tuple(datarel->rd_att, datavalues, datanulls);
@@ -396,12 +507,39 @@ CreateStatistics(CreateStatsStmt *stmt)
*/
ObjectAddressSet(myself, StatisticExtRelationId, statoid);
- for (i = 0; i < numcols; i++)
+ /* add dependencies for plain column references */
+ for (i = 0; i < nattnums; i++)
{
ObjectAddressSubSet(parentobject, RelationRelationId, relid, attnums[i]);
recordDependencyOn(&myself, &parentobject, DEPENDENCY_AUTO);
}
+ /*
+ * If there are no simply-referenced columns, give the statistics an
+ * auto dependency on the whole table. In most cases, this will
+ * be redundant, but it might not be if the statistics expressions
+ * contain no Vars (which might seem strange but possible).
+ *
+ * XXX This is copied from index_create, not sure if it's applicable
+ * to extended statistics too.
+ */
+ if (!nattnums)
+ {
+ ObjectAddressSet(parentobject, RelationRelationId, relid);
+ recordDependencyOn(&myself, &parentobject, DEPENDENCY_AUTO);
+ }
+
+ /*
+ * Store dependencies on anything mentioned in statistics expressions,
+ * just like we do for index expressions.
+ */
+ if (stxexprs)
+ recordDependencyOnSingleRelExpr(&myself,
+ (Node *) stxexprs,
+ relid,
+ DEPENDENCY_NORMAL,
+ DEPENDENCY_AUTO, false, true);
+
/*
* Also add dependencies on namespace and owner. These are required
* because the stats object might have a different namespace and/or owner
@@ -625,7 +763,7 @@ UpdateStatisticsForTypeChange(Oid statsOid, Oid relationOid, int attnum,
elog(ERROR, "cache lookup failed for statistics object %u", statsOid);
/*
- * When none of the defined statistics types contain datum values from the
+ * When none of the defined statistics kinds contain datum values from the
* table's columns then there's no need to reset the stats. Functional
* dependencies and ndistinct stats should still hold true.
*/
@@ -637,7 +775,7 @@ UpdateStatisticsForTypeChange(Oid statsOid, Oid relationOid, int attnum,
/*
* OK, we need to reset some statistics. So let's build the new tuple,
- * replacing the affected statistics types with NULL.
+ * replacing the affected statistics kinds with NULL.
*/
memset(nulls, 0, Natts_pg_statistic_ext_data * sizeof(bool));
memset(replaces, 0, Natts_pg_statistic_ext_data * sizeof(bool));
@@ -645,6 +783,7 @@ UpdateStatisticsForTypeChange(Oid statsOid, Oid relationOid, int attnum,
replaces[Anum_pg_statistic_ext_data_stxdmcv - 1] = true;
nulls[Anum_pg_statistic_ext_data_stxdmcv - 1] = true;
+ nulls[Anum_pg_statistic_ext_data_stxdexpr - 1] = true;
rel = table_open(StatisticExtDataRelationId, RowExclusiveLock);
@@ -731,18 +870,26 @@ ChooseExtendedStatisticNameAddition(List *exprs)
buf[0] = '\0';
foreach(lc, exprs)
{
- ColumnRef *cref = (ColumnRef *) lfirst(lc);
+ StatsElem *selem = (StatsElem *) lfirst(lc);
const char *name;
/* It should be one of these, but just skip if it happens not to be */
- if (!IsA(cref, ColumnRef))
+ if (!IsA(selem, StatsElem))
continue;
- name = strVal((Value *) linitial(cref->fields));
+ name = selem->name;
if (buflen > 0)
buf[buflen++] = '_'; /* insert _ between names */
+ /*
+ * FIXME use 'expr' for expressions, which have empty column names.
+ * For indexes this is handled in ChooseIndexColumnNames, but we
+ * have no such function for stats.
+ */
+ if (!name)
+ name = "expr";
+
/*
* At this point we have buflen <= NAMEDATALEN. name should be less
* than NAMEDATALEN already, but use strlcpy for paranoia.
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index ba3ccc712c..a21be7ffb1 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -2925,6 +2925,17 @@ _copyIndexElem(const IndexElem *from)
return newnode;
}
+static StatsElem *
+_copyStatsElem(const StatsElem *from)
+{
+ StatsElem *newnode = makeNode(StatsElem);
+
+ COPY_STRING_FIELD(name);
+ COPY_NODE_FIELD(expr);
+
+ return newnode;
+}
+
static ColumnDef *
_copyColumnDef(const ColumnDef *from)
{
@@ -5636,6 +5647,9 @@ copyObjectImpl(const void *from)
case T_IndexElem:
retval = _copyIndexElem(from);
break;
+ case T_StatsElem:
+ retval = _copyStatsElem(from);
+ break;
case T_ColumnDef:
retval = _copyColumnDef(from);
break;
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index a2ef853dc2..2a5421c10f 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -2593,6 +2593,16 @@ _equalIndexElem(const IndexElem *a, const IndexElem *b)
return true;
}
+
+static bool
+_equalStatsElem(const StatsElem *a, const StatsElem *b)
+{
+ COMPARE_STRING_FIELD(name);
+ COMPARE_NODE_FIELD(expr);
+
+ return true;
+}
+
static bool
_equalColumnDef(const ColumnDef *a, const ColumnDef *b)
{
@@ -3689,6 +3699,9 @@ equal(const void *a, const void *b)
case T_IndexElem:
retval = _equalIndexElem(a, b);
break;
+ case T_StatsElem:
+ retval = _equalStatsElem(a, b);
+ break;
case T_ColumnDef:
retval = _equalColumnDef(a, b);
break;
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 8392be6d44..956e8d8151 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2932,6 +2932,15 @@ _outIndexElem(StringInfo str, const IndexElem *node)
WRITE_ENUM_FIELD(nulls_ordering, SortByNulls);
}
+static void
+_outStatsElem(StringInfo str, const StatsElem *node)
+{
+ WRITE_NODE_TYPE("STATSELEM");
+
+ WRITE_STRING_FIELD(name);
+ WRITE_NODE_FIELD(expr);
+}
+
static void
_outQuery(StringInfo str, const Query *node)
{
@@ -4241,6 +4250,9 @@ outNode(StringInfo str, const void *obj)
case T_IndexElem:
_outIndexElem(str, obj);
break;
+ case T_StatsElem:
+ _outStatsElem(str, obj);
+ break;
case T_Query:
_outQuery(str, obj);
break;
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index da322b453e..1e64d52c83 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -34,6 +34,7 @@
#include "foreign/fdwapi.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
+#include "nodes/nodeFuncs.h"
#include "nodes/supportnodes.h"
#include "optimizer/clauses.h"
#include "optimizer/cost.h"
@@ -1302,6 +1303,7 @@ get_relation_constraints(PlannerInfo *root,
static List *
get_relation_statistics(RelOptInfo *rel, Relation relation)
{
+ Index varno = rel->relid;
List *statoidlist;
List *stainfos = NIL;
ListCell *l;
@@ -1316,6 +1318,7 @@ get_relation_statistics(RelOptInfo *rel, Relation relation)
HeapTuple dtup;
Bitmapset *keys = NULL;
int i;
+ List *exprs = NIL;
htup = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(statOid));
if (!HeapTupleIsValid(htup))
@@ -1334,6 +1337,49 @@ get_relation_statistics(RelOptInfo *rel, Relation relation)
for (i = 0; i < staForm->stxkeys.dim1; i++)
keys = bms_add_member(keys, staForm->stxkeys.values[i]);
+ /*
+ * preprocess expression (if any)
+ *
+ * FIXME Should we cache the result somewhere?
+ */
+ {
+ bool isnull;
+ Datum datum;
+
+ /* decode expression (if any) */
+ datum = SysCacheGetAttr(STATEXTOID, htup,
+ Anum_pg_statistic_ext_stxexprs, &isnull);
+
+ if (!isnull)
+ {
+ char *exprsString;
+
+ exprsString = TextDatumGetCString(datum);
+ exprs = (List *) stringToNode(exprsString);
+ pfree(exprsString);
+
+ /*
+ * Run the expressions through eval_const_expressions. This is not just an
+ * optimization, but is necessary, because the planner will be comparing
+ * them to similarly-processed qual clauses, and may fail to detect valid
+ * matches without this. We must not use canonicalize_qual, however,
+ * since these aren't qual expressions.
+ */
+ exprs = (List *) eval_const_expressions(NULL, (Node *) exprs);
+
+ /* May as well fix opfuncids too */
+ fix_opfuncids((Node *) exprs);
+
+ /*
+ * Modify the copies we obtain from the relcache to have the
+ * correct varno for the parent relation, so that they match up
+ * correctly against qual clauses.
+ */
+ if (varno != 1)
+ ChangeVarNodes((Node *) exprs, 1, varno, 0);
+ }
+ }
+
/* add one StatisticExtInfo for each kind built */
if (statext_is_kind_built(dtup, STATS_EXT_NDISTINCT))
{
@@ -1343,6 +1389,7 @@ get_relation_statistics(RelOptInfo *rel, Relation relation)
info->rel = rel;
info->kind = STATS_EXT_NDISTINCT;
info->keys = bms_copy(keys);
+ info->exprs = exprs;
stainfos = lappend(stainfos, info);
}
@@ -1355,6 +1402,7 @@ get_relation_statistics(RelOptInfo *rel, Relation relation)
info->rel = rel;
info->kind = STATS_EXT_DEPENDENCIES;
info->keys = bms_copy(keys);
+ info->exprs = exprs;
stainfos = lappend(stainfos, info);
}
@@ -1367,6 +1415,20 @@ get_relation_statistics(RelOptInfo *rel, Relation relation)
info->rel = rel;
info->kind = STATS_EXT_MCV;
info->keys = bms_copy(keys);
+ info->exprs = exprs;
+
+ stainfos = lappend(stainfos, info);
+ }
+
+ if (statext_is_kind_built(dtup, STATS_EXT_EXPRESSIONS))
+ {
+ StatisticExtInfo *info = makeNode(StatisticExtInfo);
+
+ info->statOid = statOid;
+ info->rel = rel;
+ info->kind = STATS_EXT_EXPRESSIONS;
+ info->keys = bms_copy(keys);
+ info->exprs = exprs;
stainfos = lappend(stainfos, info);
}
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 31c95443a5..d219976b53 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -232,6 +232,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
WindowDef *windef;
JoinExpr *jexpr;
IndexElem *ielem;
+ StatsElem *selem;
Alias *alias;
RangeVar *range;
IntoClause *into;
@@ -396,7 +397,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
old_aggr_definition old_aggr_list
oper_argtypes RuleActionList RuleActionMulti
opt_column_list columnList opt_name_list
- sort_clause opt_sort_clause sortby_list index_params
+ sort_clause opt_sort_clause sortby_list index_params stats_params
opt_include opt_c_include index_including_params
name_list role_list from_clause from_list opt_array_bounds
qualified_name_list any_name any_name_list type_name_list
@@ -500,6 +501,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
%type <list> func_alias_clause
%type <sortby> sortby
%type <ielem> index_elem index_elem_options
+%type <selem> stats_param
%type <node> table_ref
%type <jexpr> joined_table
%type <range> relation_expr
@@ -4049,7 +4051,7 @@ ExistingIndex: USING INDEX name { $$ = $3; }
CreateStatsStmt:
CREATE STATISTICS any_name
- opt_name_list ON expr_list FROM from_list
+ opt_name_list ON stats_params FROM from_list
{
CreateStatsStmt *n = makeNode(CreateStatsStmt);
n->defnames = $3;
@@ -4061,7 +4063,7 @@ CreateStatsStmt:
$$ = (Node *)n;
}
| CREATE STATISTICS IF_P NOT EXISTS any_name
- opt_name_list ON expr_list FROM from_list
+ opt_name_list ON stats_params FROM from_list
{
CreateStatsStmt *n = makeNode(CreateStatsStmt);
n->defnames = $6;
@@ -4074,6 +4076,36 @@ CreateStatsStmt:
}
;
+/*
+ * Statistics attributes can be either simple column references, or arbitrary
+ * expressions in parens. For compatibility with index attributes permitted
+ * in CREATE INDEX, we allow an expression that's just a function call to be
+ * written without parens.
+ */
+
+stats_params: stats_param { $$ = list_make1($1); }
+ | stats_params ',' stats_param { $$ = lappend($1, $3); }
+ ;
+
+stats_param: ColId
+ {
+ $$ = makeNode(StatsElem);
+ $$->name = $1;
+ $$->expr = NULL;
+ }
+ | func_expr_windowless
+ {
+ $$ = makeNode(StatsElem);
+ $$->name = NULL;
+ $$->expr = $1;
+ }
+ | '(' a_expr ')'
+ {
+ $$ = makeNode(StatsElem);
+ $$->name = NULL;
+ $$->expr = $2;
+ }
+ ;
/*****************************************************************************
*
diff --git a/src/backend/parser/parse_agg.c b/src/backend/parser/parse_agg.c
index 588f005dd9..0b0841afb9 100644
--- a/src/backend/parser/parse_agg.c
+++ b/src/backend/parser/parse_agg.c
@@ -484,6 +484,13 @@ check_agglevels_and_constraints(ParseState *pstate, Node *expr)
else
err = _("grouping operations are not allowed in index predicates");
+ break;
+ case EXPR_KIND_STATS_EXPRESSION:
+ if (isAgg)
+ err = _("aggregate functions are not allowed in statistics expressions");
+ else
+ err = _("grouping operations are not allowed in statistics expressions");
+
break;
case EXPR_KIND_ALTER_COL_TRANSFORM:
if (isAgg)
@@ -906,6 +913,9 @@ transformWindowFuncCall(ParseState *pstate, WindowFunc *wfunc,
case EXPR_KIND_INDEX_EXPRESSION:
err = _("window functions are not allowed in index expressions");
break;
+ case EXPR_KIND_STATS_EXPRESSION:
+ err = _("window functions are not allowed in statistics expressions");
+ break;
case EXPR_KIND_INDEX_PREDICATE:
err = _("window functions are not allowed in index predicates");
break;
diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index 379355f9bf..fcc1bb33d1 100644
--- a/src/backend/parser/parse_expr.c
+++ b/src/backend/parser/parse_expr.c
@@ -500,6 +500,7 @@ transformColumnRef(ParseState *pstate, ColumnRef *cref)
case EXPR_KIND_FUNCTION_DEFAULT:
case EXPR_KIND_INDEX_EXPRESSION:
case EXPR_KIND_INDEX_PREDICATE:
+ case EXPR_KIND_STATS_EXPRESSION:
case EXPR_KIND_ALTER_COL_TRANSFORM:
case EXPR_KIND_EXECUTE_PARAMETER:
case EXPR_KIND_TRIGGER_WHEN:
@@ -1739,6 +1740,9 @@ transformSubLink(ParseState *pstate, SubLink *sublink)
case EXPR_KIND_INDEX_PREDICATE:
err = _("cannot use subquery in index predicate");
break;
+ case EXPR_KIND_STATS_EXPRESSION:
+ err = _("cannot use subquery in statistics expression");
+ break;
case EXPR_KIND_ALTER_COL_TRANSFORM:
err = _("cannot use subquery in transform expression");
break;
@@ -3028,6 +3032,8 @@ ParseExprKindName(ParseExprKind exprKind)
return "index expression";
case EXPR_KIND_INDEX_PREDICATE:
return "index predicate";
+ case EXPR_KIND_STATS_EXPRESSION:
+ return "statistics expression";
case EXPR_KIND_ALTER_COL_TRANSFORM:
return "USING";
case EXPR_KIND_EXECUTE_PARAMETER:
diff --git a/src/backend/parser/parse_func.c b/src/backend/parser/parse_func.c
index 07d0013e84..652930ddf9 100644
--- a/src/backend/parser/parse_func.c
+++ b/src/backend/parser/parse_func.c
@@ -2503,6 +2503,9 @@ check_srf_call_placement(ParseState *pstate, Node *last_srf, int location)
case EXPR_KIND_INDEX_PREDICATE:
err = _("set-returning functions are not allowed in index predicates");
break;
+ case EXPR_KIND_STATS_EXPRESSION:
+ err = _("set-returning functions are not allowed in statistics expressions");
+ break;
case EXPR_KIND_ALTER_COL_TRANSFORM:
err = _("set-returning functions are not allowed in transform expressions");
break;
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index b31f3afa03..0028240d1a 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -1898,6 +1898,9 @@ generateClonedExtStatsStmt(RangeVar *heapRel, Oid heapRelid,
stat_types = lappend(stat_types, makeString("dependencies"));
else if (enabled[i] == STATS_EXT_MCV)
stat_types = lappend(stat_types, makeString("mcv"));
+ else if (enabled[i] == STATS_EXT_EXPRESSIONS)
+ /* expression stats are not exposed to users */
+ continue;
else
elog(ERROR, "unrecognized statistics kind %c", enabled[i]);
}
@@ -1905,14 +1908,43 @@ generateClonedExtStatsStmt(RangeVar *heapRel, Oid heapRelid,
/* Determine which columns the statistics are on */
for (i = 0; i < statsrec->stxkeys.dim1; i++)
{
- ColumnRef *cref = makeNode(ColumnRef);
+ StatsElem *selem = makeNode(StatsElem);
AttrNumber attnum = statsrec->stxkeys.values[i];
- cref->fields = list_make1(makeString(get_attname(heapRelid,
- attnum, false)));
- cref->location = -1;
+ selem->name = get_attname(heapRelid, attnum, false);
+ selem->expr = NULL;
- def_names = lappend(def_names, cref);
+ def_names = lappend(def_names, selem);
+ }
+
+ /*
+ * Now handle expressions, if there are any. The order does not
+ * matter for extended stats, so we simply append them after
+ * simple column references.
+ */
+ datum = SysCacheGetAttr(STATEXTOID, ht_stats,
+ Anum_pg_statistic_ext_stxexprs, &isnull);
+
+ if (!isnull)
+ {
+ ListCell *lc;
+ List *exprs = NIL;
+ char *exprsString;
+
+ exprsString = TextDatumGetCString(datum);
+ exprs = (List *) stringToNode(exprsString);
+
+ foreach(lc, exprs)
+ {
+ StatsElem *selem = makeNode(StatsElem);
+
+ selem->name = NULL;
+ selem->expr = (Node *) lfirst(lc);
+
+ def_names = lappend(def_names, selem);
+ }
+
+ pfree(exprsString);
}
/* finally, build the output node */
@@ -1923,6 +1955,7 @@ generateClonedExtStatsStmt(RangeVar *heapRel, Oid heapRelid,
stats->relations = list_make1(heapRel);
stats->stxcomment = NULL;
stats->if_not_exists = false;
+ stats->transformed = true; /* don't need transformStatsStmt */
/* Clean up */
ReleaseSysCache(ht_stats);
@@ -2847,6 +2880,84 @@ transformIndexStmt(Oid relid, IndexStmt *stmt, const char *queryString)
return stmt;
}
+/*
+ * transformStatsStmt - parse analysis for CREATE STATISTICS
+ *
+ * To avoid race conditions, it's important that this function rely only on
+ * the passed-in relid (and not on stmt->relation) to determine the target
+ * relation.
+ */
+CreateStatsStmt *
+transformStatsStmt(Oid relid, CreateStatsStmt *stmt, const char *queryString)
+{
+ ParseState *pstate;
+ ParseNamespaceItem *nsitem;
+ ListCell *l;
+ Relation rel;
+
+ /* Nothing to do if statement already transformed. */
+ if (stmt->transformed)
+ return stmt;
+
+ /*
+ * We must not scribble on the passed-in CreateStatsStmt, so copy it. (This is
+ * overkill, but easy.)
+ */
+ stmt = copyObject(stmt);
+
+ /* Set up pstate */
+ pstate = make_parsestate(NULL);
+ pstate->p_sourcetext = queryString;
+
+ /*
+ * Put the parent table into the rtable so that the expressions can refer
+ * to its fields without qualification. Caller is responsible for locking
+ * relation, but we still need to open it.
+ */
+ rel = relation_open(relid, NoLock);
+ nsitem = addRangeTableEntryForRelation(pstate, rel,
+ AccessShareLock,
+ NULL, false, true);
+
+ /* no to join list, yes to namespaces */
+ addNSItemToQuery(pstate, nsitem, false, true, true);
+
+ /* take care of any expressions */
+ foreach(l, stmt->exprs)
+ {
+ StatsElem *selem = (StatsElem *) lfirst(l);
+
+ if (selem->expr)
+ {
+ /* Now do parse transformation of the expression */
+ selem->expr = transformExpr(pstate, selem->expr,
+ EXPR_KIND_STATS_EXPRESSION);
+
+ /* We have to fix its collations too */
+ assign_expr_collations(pstate, selem->expr);
+ }
+ }
+
+ /*
+ * Check that only the base rel is mentioned. (This should be dead code
+ * now that add_missing_from is history.)
+ */
+ if (list_length(pstate->p_rtable) != 1)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
+ errmsg("statistics expressions and predicates can refer only to the table being indexed")));
+
+ free_parsestate(pstate);
+
+ /* Close relation */
+ table_close(rel, NoLock);
+
+ /* Mark statement as successfully transformed */
+ stmt->transformed = true;
+
+ return stmt;
+}
+
/*
* transformRuleStmt -
diff --git a/src/backend/statistics/dependencies.c b/src/backend/statistics/dependencies.c
index f6e399b192..6bf3127bcc 100644
--- a/src/backend/statistics/dependencies.c
+++ b/src/backend/statistics/dependencies.c
@@ -70,15 +70,18 @@ static void generate_dependencies(DependencyGenerator state);
static DependencyGenerator DependencyGenerator_init(int n, int k);
static void DependencyGenerator_free(DependencyGenerator state);
static AttrNumber *DependencyGenerator_next(DependencyGenerator state);
-static double dependency_degree(int numrows, HeapTuple *rows, int k,
- AttrNumber *dependency, VacAttrStats **stats, Bitmapset *attrs);
+static double dependency_degree(int numrows, HeapTuple *rows,
+ ExprInfo *exprs, int k,
+ AttrNumber *dependency, VacAttrStats **stats,
+ Bitmapset *attrs);
static bool dependency_is_fully_matched(MVDependency *dependency,
Bitmapset *attnums);
static bool dependency_is_compatible_clause(Node *clause, Index relid,
AttrNumber *attnum);
+static bool dependency_is_compatible_expression(Node *clause, Index relid,
+ List *statlist, Node **expr);
static MVDependency *find_strongest_dependency(MVDependencies **dependencies,
- int ndependencies,
- Bitmapset *attnums);
+ int ndependencies, Bitmapset *attnums);
static Selectivity clauselist_apply_dependencies(PlannerInfo *root, List *clauses,
int varRelid, JoinType jointype,
SpecialJoinInfo *sjinfo,
@@ -219,8 +222,9 @@ DependencyGenerator_next(DependencyGenerator state)
* the last one.
*/
static double
-dependency_degree(int numrows, HeapTuple *rows, int k, AttrNumber *dependency,
- VacAttrStats **stats, Bitmapset *attrs)
+dependency_degree(int numrows, HeapTuple *rows, ExprInfo *exprs, int k,
+ AttrNumber *dependency, VacAttrStats **stats,
+ Bitmapset *attrs)
{
int i,
nitems;
@@ -289,8 +293,8 @@ dependency_degree(int numrows, HeapTuple *rows, int k, AttrNumber *dependency,
* descriptor. For now that assumption holds, but it might change in the
* future for example if we support statistics on multiple tables.
*/
- items = build_sorted_items(numrows, &nitems, rows, stats[0]->tupDesc,
- mss, k, attnums_dep);
+ items = build_sorted_items(numrows, &nitems, rows, exprs,
+ stats[0]->tupDesc, mss, k, attnums_dep);
/*
* Walk through the sorted array, split it into rows according to the
@@ -360,7 +364,8 @@ dependency_degree(int numrows, HeapTuple *rows, int k, AttrNumber *dependency,
* (c) -> b
*/
MVDependencies *
-statext_dependencies_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
+statext_dependencies_build(int numrows, HeapTuple *rows,
+ ExprInfo *exprs, Bitmapset *attrs,
VacAttrStats **stats)
{
int i,
@@ -371,6 +376,9 @@ statext_dependencies_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
/* result */
MVDependencies *dependencies = NULL;
+ /* treat expressions as special attributes with high attnums */
+ attrs = add_expressions_to_attributes(attrs, exprs->nexprs);
+
/*
* Transform the bms into an array, to make accessing i-th member easier.
*/
@@ -398,7 +406,8 @@ statext_dependencies_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
MVDependency *d;
/* compute how valid the dependency seems */
- degree = dependency_degree(numrows, rows, k, dependency, stats, attrs);
+ degree = dependency_degree(numrows, rows, exprs, k, dependency,
+ stats, attrs);
/*
* if the dependency seems entirely invalid, don't store it
@@ -441,6 +450,8 @@ statext_dependencies_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
DependencyGenerator_free(DependencyGenerator);
}
+ pfree(attrs);
+
return dependencies;
}
@@ -639,7 +650,7 @@ statext_dependencies_load(Oid mvoid)
Anum_pg_statistic_ext_data_stxddependencies, &isnull);
if (isnull)
elog(ERROR,
- "requested statistic kind \"%c\" is not yet built for statistics object %u",
+ "requested statistics kind \"%c\" is not yet built for statistics object %u",
STATS_EXT_DEPENDENCIES, mvoid);
result = statext_dependencies_deserialize(DatumGetByteaPP(deps));
@@ -1157,6 +1168,134 @@ clauselist_apply_dependencies(PlannerInfo *root, List *clauses,
return s1;
}
+/*
+ * dependency_is_compatible_expression
+ * Determines if the expression is compatible with functional dependencies
+ *
+ * Similar to dependency_is_compatible_clause, but doesn't enforce that the
+ * expression is a simple Var. OTOH we check that there's at least one
+ * statistics object matching the expression.
+ */
+static bool
+dependency_is_compatible_expression(Node *clause, Index relid, List *statlist, Node **expr)
+{
+ List *vars;
+ ListCell *lc, *lc2;
+
+ RestrictInfo *rinfo = (RestrictInfo *) clause;
+ Node *clause_expr;
+
+ if (!IsA(rinfo, RestrictInfo))
+ return false;
+
+ /* Pseudoconstants are not interesting (they couldn't contain a Var) */
+ if (rinfo->pseudoconstant)
+ return false;
+
+ /* Clauses referencing multiple, or no, varnos are incompatible */
+ if (bms_membership(rinfo->clause_relids) != BMS_SINGLETON)
+ return false;
+
+ if (is_opclause(rinfo->clause))
+ {
+ /* If it's an opclause, check for Var = Const or Const = Var. */
+ OpExpr *expr = (OpExpr *) rinfo->clause;
+
+ /* Only expressions with two arguments are candidates. */
+ if (list_length(expr->args) != 2)
+ return false;
+
+ /* Make sure non-selected argument is a pseudoconstant. */
+ if (is_pseudo_constant_clause(lsecond(expr->args)))
+ clause_expr = linitial(expr->args);
+ else if (is_pseudo_constant_clause(linitial(expr->args)))
+ clause_expr = lsecond(expr->args);
+ else
+ return false;
+
+ /*
+ * If it's not an "=" operator, just ignore the clause, as it's not
+ * compatible with functional dependencies.
+ *
+ * This uses the function for estimating selectivity, not the operator
+ * directly (a bit awkward, but well ...).
+ *
+ * XXX this is pretty dubious; probably it'd be better to check btree
+ * or hash opclass membership, so as not to be fooled by custom
+ * selectivity functions, and to be more consistent with decisions
+ * elsewhere in the planner.
+ */
+ if (get_oprrest(expr->opno) != F_EQSEL)
+ return false;
+
+ /* OK to proceed with checking "var" */
+ }
+ else if (is_notclause(rinfo->clause))
+ {
+ /*
+ * "NOT x" can be interpreted as "x = false", so get the argument and
+ * proceed with seeing if it's a suitable Var.
+ */
+ clause_expr = (Node *) get_notclausearg(rinfo->clause);
+ }
+ else
+ {
+ /*
+ * A boolean expression "x" can be interpreted as "x = true", so
+ * proceed with seeing if it's a suitable Var.
+ */
+ clause_expr = (Node *) rinfo->clause;
+ }
+
+ /*
+ * We may ignore any RelabelType node above the operand. (There won't be
+ * more than one, since eval_const_expressions has been applied already.)
+ */
+ if (IsA(clause_expr, RelabelType))
+ clause_expr = (Node *) ((RelabelType *) clause_expr)->arg;
+
+ vars = pull_var_clause(clause_expr, 0);
+
+ foreach (lc, vars)
+ {
+ Var *var = (Var *) lfirst(lc);
+
+ /* Ensure Var is from the correct relation */
+ if (var->varno != relid)
+ return false;
+
+ /* We also better ensure the Var is from the current level */
+ if (var->varlevelsup != 0)
+ return false;
+
+ /* Also ignore system attributes (we don't allow stats on those) */
+ if (!AttrNumberIsForUserDefinedAttr(var->varattno))
+ return false;
+ }
+
+ foreach (lc, statlist)
+ {
+ StatisticExtInfo *info = (StatisticExtInfo *) lfirst(lc);
+
+ /* ignore stats without dependencies */
+ if (info->kind != STATS_EXT_DEPENDENCIES)
+ continue;
+
+ foreach (lc2, info->exprs)
+ {
+ Node *stat_expr = (Node *) lfirst(lc2);
+
+ if (equal(clause_expr, stat_expr))
+ {
+ *expr = stat_expr;
+ return true;
+ }
+ }
+ }
+
+ return false;
+}
+
/*
* dependencies_clauselist_selectivity
* Return the estimated selectivity of (a subset of) the given clauses
@@ -1205,6 +1344,10 @@ dependencies_clauselist_selectivity(PlannerInfo *root,
int ndependencies;
int i;
+ /* unique expressions */
+ Node **unique_exprs;
+ int unique_exprs_cnt;
+
/* check if there's any stats that might be useful for us. */
if (!has_stats_of_kind(rel->statlist, STATS_EXT_DEPENDENCIES))
return 1.0;
@@ -1212,6 +1355,14 @@ dependencies_clauselist_selectivity(PlannerInfo *root,
list_attnums = (AttrNumber *) palloc(sizeof(AttrNumber) *
list_length(clauses));
+ /*
+ * We allocate space as if every clause was a unique expression, although
+ * that's probably overkill. Some will be simple column references that
+ * we'll translate to attnums, and there might be duplicates.
+ */
+ unique_exprs = (Node **) palloc(sizeof(Node *) * list_length(clauses));
+ unique_exprs_cnt = 0;
+
/*
* Pre-process the clauses list to extract the attnums seen in each item.
* We need to determine if there's any clauses which will be useful for
@@ -1222,29 +1373,76 @@ dependencies_clauselist_selectivity(PlannerInfo *root,
*
* We also skip clauses that we already estimated using different types of
* statistics (we treat them as incompatible).
+ *
+ * For expressions, we generate attnums higher than MaxHeapAttributeNumber
+ * so that we can work with attnums only.
*/
listidx = 0;
foreach(l, clauses)
{
Node *clause = (Node *) lfirst(l);
AttrNumber attnum;
+ Node *expr = NULL;
- if (!bms_is_member(listidx, *estimatedclauses) &&
- dependency_is_compatible_clause(clause, rel->relid, &attnum))
+ /* ignore clause by default */
+ list_attnums[listidx] = InvalidAttrNumber;
+
+ if (!bms_is_member(listidx, *estimatedclauses))
{
- list_attnums[listidx] = attnum;
- clauses_attnums = bms_add_member(clauses_attnums, attnum);
+ /*
+ * If it's a simple column refrence, just extract the attnum. If
+ * it's an expression, make sure it's not a duplicate and assign
+ * a special attnum to it (higher than any regular value).
+ */
+ if (dependency_is_compatible_clause(clause, rel->relid, &attnum))
+ {
+ list_attnums[listidx] = attnum;
+ clauses_attnums = bms_add_member(clauses_attnums, attnum);
+ }
+ else if (dependency_is_compatible_expression(clause, rel->relid,
+ rel->statlist,
+ &expr))
+ {
+ /* special attnum assigned to this expression */
+ attnum = InvalidAttrNumber;
+
+ Assert(expr != NULL);
+
+ /* If the expression is duplicate, use the same attnum. */
+ for (i = 0; i < unique_exprs_cnt; i++)
+ {
+ if (equal(unique_exprs[i], expr))
+ {
+ attnum = EXPRESSION_ATTNUM(i);
+ break;
+ }
+ }
+
+ /* not found in the list, so add it */
+ if (attnum == InvalidAttrNumber)
+ {
+ attnum = EXPRESSION_ATTNUM(unique_exprs_cnt);
+ unique_exprs[unique_exprs_cnt++] = expr;
+
+ /* shouldn't have seen this attnum yet */
+ Assert(!bms_is_member(attnum, clauses_attnums));
+
+ /* we may add the attnum repeatedly to clauses_attnums */
+ clauses_attnums = bms_add_member(clauses_attnums, attnum);
+ }
+
+ /* remember which attnum was assigned to this clause */
+ list_attnums[listidx] = attnum;
+ }
}
- else
- list_attnums[listidx] = InvalidAttrNumber;
listidx++;
}
/*
- * If there's not at least two distinct attnums then reject the whole list
- * of clauses. We must return 1.0 so the calling function's selectivity is
- * unaffected.
+ * If there's not at least two distinct attnums and expressions, then
+ * reject the whole list of clauses. We must return 1.0 so the calling
+ * function's selectivity is unaffected.
*/
if (bms_membership(clauses_attnums) != BMS_MULTIPLE)
{
@@ -1273,25 +1471,138 @@ dependencies_clauselist_selectivity(PlannerInfo *root,
{
StatisticExtInfo *stat = (StatisticExtInfo *) lfirst(l);
Bitmapset *matched;
- BMS_Membership membership;
+ int nmatched;
+ int nexprs;
+ MVDependencies *deps;
/* skip statistics that are not of the correct type */
if (stat->kind != STATS_EXT_DEPENDENCIES)
continue;
+ /* count matching simple clauses */
matched = bms_intersect(clauses_attnums, stat->keys);
- membership = bms_membership(matched);
+ nmatched = bms_num_members(matched);
bms_free(matched);
- /* skip objects matching fewer than two attributes from clauses */
- if (membership != BMS_MULTIPLE)
+ /* count matching expressions */
+ nexprs = 0;
+ for (i = 0; i < unique_exprs_cnt; i++)
+ {
+ ListCell *lc;
+
+ foreach (lc, stat->exprs)
+ {
+ Node *stat_expr = (Node *) lfirst(lc);
+
+ /* try to match it */
+ if (equal(stat_expr, unique_exprs[i]))
+ nexprs++;
+ }
+ }
+
+ /*
+ * Skip objects matching fewer than two attributes/expressions
+ * from clauses.
+ */
+ if (nmatched + nexprs < 2)
continue;
- func_dependencies[nfunc_dependencies]
- = statext_dependencies_load(stat->statOid);
+ deps = statext_dependencies_load(stat->statOid);
- total_ndeps += func_dependencies[nfunc_dependencies]->ndeps;
- nfunc_dependencies++;
+ /*
+ * The expressions may be represented by different attnums in the
+ * stats, we need to remap them to be consistent with the clauses.
+ * That will make the later steps (e.g. picking the strongest item
+ * and so on) much simpler.
+ *
+ * When we're at it, we can also remove dependencies referencing
+ * missing clauses (i.e. expressions that are not in the clauses).
+ *
+ * XXX We might also skip clauses referencing missing attnums, not
+ * just expressions.
+ */
+ if (stat->exprs)
+ {
+ int ndeps = 0;
+
+ for (i = 0; i < deps->ndeps; i++)
+ {
+ bool skip = false;
+ MVDependency *dep = deps->deps[i];
+ int j;
+
+ for (j = 0; j < dep->nattributes; j++)
+ {
+ int idx;
+ Node *expr;
+ int k;
+ AttrNumber unique_attnum = InvalidAttrNumber;
+
+ /* regular attribute, no need to remap */
+ if (dep->attributes[j] <= MaxHeapAttributeNumber)
+ continue;
+
+ /* index of the expression */
+ idx = EXPRESSION_INDEX(dep->attributes[j]);
+
+ /* make sure the expression index is valid */
+ Assert((idx >= 0) && (idx < list_length(stat->exprs)));
+
+ expr = (Node *) list_nth(stat->exprs, idx);
+
+ /* try to find the expression in the unique list */
+ for (k = 0; k < unique_exprs_cnt; k++)
+ {
+ /*
+ * found a matching unique expression, use the attnum
+ * (derived from index of the unique expression)
+ */
+ if (equal(unique_exprs[k], expr))
+ {
+ unique_attnum = EXPRESSION_ATTNUM(k);
+ break;
+ }
+ }
+
+ /*
+ * Not found a matching expression, so we can simply
+ * skip this dependency, because there's no chance it
+ * will be fully covered.
+ */
+ if (unique_attnum == InvalidAttrNumber)
+ {
+ skip = true;
+ break;
+ }
+
+ /* otherwise remap it to the new attnum */
+ dep->attributes[j] = unique_attnum;
+ }
+
+ /* if found a matching, */
+ if (!skip)
+ {
+ /* maybe we've skipped something earlier, so move it */
+ if (ndeps != i)
+ deps->deps[ndeps] = deps->deps[i];
+
+ ndeps++;
+ }
+ }
+
+ deps->ndeps = ndeps;
+ }
+
+ /*
+ * It's possible we've removed all dependencies, in which case we
+ * don't bother adding it to the list.
+ */
+ if (deps->ndeps > 0)
+ {
+ func_dependencies[nfunc_dependencies] = deps;
+ total_ndeps += deps->ndeps;
+ nfunc_dependencies++;
+ }
}
/* if no matching stats could be found then we've nothing to do */
@@ -1300,6 +1611,7 @@ dependencies_clauselist_selectivity(PlannerInfo *root,
pfree(func_dependencies);
bms_free(clauses_attnums);
pfree(list_attnums);
+ pfree(unique_exprs);
return 1.0;
}
@@ -1347,6 +1659,7 @@ dependencies_clauselist_selectivity(PlannerInfo *root,
pfree(func_dependencies);
bms_free(clauses_attnums);
pfree(list_attnums);
+ pfree(unique_exprs);
return s1;
}
diff --git a/src/backend/statistics/extended_stats.c b/src/backend/statistics/extended_stats.c
index a030ea3653..ace6061b20 100644
--- a/src/backend/statistics/extended_stats.c
+++ b/src/backend/statistics/extended_stats.c
@@ -24,6 +24,7 @@
#include "catalog/pg_collation.h"
#include "catalog/pg_statistic_ext.h"
#include "catalog/pg_statistic_ext_data.h"
+#include "executor/executor.h"
#include "commands/progress.h"
#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
@@ -35,13 +36,16 @@
#include "statistics/statistics.h"
#include "utils/acl.h"
#include "utils/array.h"
+#include "utils/attoptcache.h"
#include "utils/builtins.h"
+#include "utils/datum.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/selfuncs.h"
#include "utils/syscache.h"
+#include "utils/typcache.h"
/*
* To avoid consuming too much memory during analysis and/or too much space
@@ -64,20 +68,37 @@ typedef struct StatExtEntry
char *schema; /* statistics object's schema */
char *name; /* statistics object's name */
Bitmapset *columns; /* attribute numbers covered by the object */
- List *types; /* 'char' list of enabled statistic kinds */
+ List *types; /* 'char' list of enabled statistics kinds */
int stattarget; /* statistics target (-1 for default) */
+ List *exprs; /* expressions */
} StatExtEntry;
static List *fetch_statentries_for_relation(Relation pg_statext, Oid relid);
-static VacAttrStats **lookup_var_attr_stats(Relation rel, Bitmapset *attrs,
+static VacAttrStats **lookup_var_attr_stats(Relation rel, Bitmapset *attrs, List *exprs,
int nvacatts, VacAttrStats **vacatts);
-static void statext_store(Oid relid,
+static void statext_store(Oid statOid,
MVNDistinct *ndistinct, MVDependencies *dependencies,
- MCVList *mcv, VacAttrStats **stats);
+ MCVList *mcv, Datum exprs, VacAttrStats **stats);
static int statext_compute_stattarget(int stattarget,
int natts, VacAttrStats **stats);
+typedef struct AnlExprData
+{
+ Node *expr; /* expression to analyze */
+ VacAttrStats *vacattrstat; /* index attrs to analyze */
+} AnlExprData;
+
+static void compute_expr_stats(Relation onerel, double totalrows,
+ AnlExprData *exprdata, int nexprs,
+ HeapTuple *rows, int numrows);
+static Datum serialize_expr_stats(AnlExprData *exprdata, int nexprs);
+static Datum expr_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
+static AnlExprData *build_expr_data(List *exprs);
+static VacAttrStats *examine_expression(Node *expr);
+static ExprInfo *evaluate_expressions(Relation rel, List *exprs,
+ int numrows, HeapTuple *rows);
+
/*
* Compute requested extended stats, using the rows sampled for the plain
* (single-column) stats.
@@ -92,7 +113,7 @@ BuildRelationExtStatistics(Relation onerel, double totalrows,
{
Relation pg_stext;
ListCell *lc;
- List *stats;
+ List *statslist;
MemoryContext cxt;
MemoryContext oldcxt;
int64 ext_cnt;
@@ -103,10 +124,10 @@ BuildRelationExtStatistics(Relation onerel, double totalrows,
oldcxt = MemoryContextSwitchTo(cxt);
pg_stext = table_open(StatisticExtRelationId, RowExclusiveLock);
- stats = fetch_statentries_for_relation(pg_stext, RelationGetRelid(onerel));
+ statslist = fetch_statentries_for_relation(pg_stext, RelationGetRelid(onerel));
/* report this phase */
- if (stats != NIL)
+ if (statslist != NIL)
{
const int index[] = {
PROGRESS_ANALYZE_PHASE,
@@ -114,28 +135,31 @@ BuildRelationExtStatistics(Relation onerel, double totalrows,
};
const int64 val[] = {
PROGRESS_ANALYZE_PHASE_COMPUTE_EXT_STATS,
- list_length(stats)
+ list_length(statslist)
};
pgstat_progress_update_multi_param(2, index, val);
}
ext_cnt = 0;
- foreach(lc, stats)
+ foreach(lc, statslist)
{
StatExtEntry *stat = (StatExtEntry *) lfirst(lc);
MVNDistinct *ndistinct = NULL;
MVDependencies *dependencies = NULL;
MCVList *mcv = NULL;
+ Datum exprstats = (Datum) 0;
VacAttrStats **stats;
ListCell *lc2;
int stattarget;
+ ExprInfo *exprs;
+ int min_attrs;
/*
* Check if we can build these stats based on the column analyzed. If
* not, report this fact (except in autovacuum) and move on.
*/
- stats = lookup_var_attr_stats(onerel, stat->columns,
+ stats = lookup_var_attr_stats(onerel, stat->columns, stat->exprs,
natts, vacattrstats);
if (!stats)
{
@@ -150,9 +174,28 @@ BuildRelationExtStatistics(Relation onerel, double totalrows,
continue;
}
+ /* determine the minimum required number of attributes/expressions */
+ min_attrs = 1;
+ foreach(lc2, stat->types)
+ {
+ char t = (char) lfirst_int(lc2);
+
+ switch (t)
+ {
+ /* expressions only need a single item */
+ case STATS_EXT_EXPRESSIONS:
+ break;
+
+ /* all other statistics kinds require at least two */
+ default:
+ min_attrs = 2;
+ break;
+ }
+ }
+
/* check allowed number of dimensions */
- Assert(bms_num_members(stat->columns) >= 2 &&
- bms_num_members(stat->columns) <= STATS_MAX_DIMENSIONS);
+ Assert(bms_num_members(stat->columns) + list_length(stat->exprs) >= min_attrs &&
+ bms_num_members(stat->columns) + list_length(stat->exprs) <= STATS_MAX_DIMENSIONS);
/* compute statistics target for this statistics */
stattarget = statext_compute_stattarget(stat->stattarget,
@@ -167,6 +210,9 @@ BuildRelationExtStatistics(Relation onerel, double totalrows,
if (stattarget == 0)
continue;
+ /* evaluate expressions (if the statistics has any) */
+ exprs = evaluate_expressions(onerel, stat->exprs, numrows, rows);
+
/* compute statistic of each requested type */
foreach(lc2, stat->types)
{
@@ -174,21 +220,43 @@ BuildRelationExtStatistics(Relation onerel, double totalrows,
if (t == STATS_EXT_NDISTINCT)
ndistinct = statext_ndistinct_build(totalrows, numrows, rows,
- stat->columns, stats);
+ exprs, stat->columns,
+ stats);
else if (t == STATS_EXT_DEPENDENCIES)
dependencies = statext_dependencies_build(numrows, rows,
- stat->columns, stats);
+ exprs, stat->columns,
+ stats);
else if (t == STATS_EXT_MCV)
- mcv = statext_mcv_build(numrows, rows, stat->columns, stats,
- totalrows, stattarget);
+ mcv = statext_mcv_build(numrows, rows, exprs, stat->columns,
+ stats, totalrows, stattarget);
+ else if (t == STATS_EXT_EXPRESSIONS)
+ {
+ AnlExprData *exprdata;
+ int nexprs;
+
+ /* should not happen, thanks to checks when defining stats */
+ if (!stat->exprs)
+ elog(ERROR, "requested expression stats, but there are no expressions");
+
+ exprdata = build_expr_data(stat->exprs);
+ nexprs = list_length(stat->exprs);
+
+ compute_expr_stats(onerel, totalrows,
+ exprdata, nexprs,
+ rows, numrows);
+
+ exprstats = serialize_expr_stats(exprdata, nexprs);
+ }
}
/* store the statistics in the catalog */
- statext_store(stat->statOid, ndistinct, dependencies, mcv, stats);
+ statext_store(stat->statOid, ndistinct, dependencies, mcv, exprstats, stats);
/* for reporting progress */
pgstat_progress_update_param(PROGRESS_ANALYZE_EXT_STATS_COMPUTED,
++ext_cnt);
+
+ pfree(exprs);
}
table_close(pg_stext, RowExclusiveLock);
@@ -241,7 +309,7 @@ ComputeExtStatisticsRows(Relation onerel,
* analyzed. If not, ignore it (don't report anything, we'll do that
* during the actual build BuildRelationExtStatistics).
*/
- stats = lookup_var_attr_stats(onerel, stat->columns,
+ stats = lookup_var_attr_stats(onerel, stat->columns, stat->exprs,
natts, vacattrstats);
if (!stats)
@@ -349,6 +417,10 @@ statext_is_kind_built(HeapTuple htup, char type)
attnum = Anum_pg_statistic_ext_data_stxdmcv;
break;
+ case STATS_EXT_EXPRESSIONS:
+ attnum = Anum_pg_statistic_ext_data_stxdexpr;
+ break;
+
default:
elog(ERROR, "unexpected statistics type requested: %d", type);
}
@@ -388,6 +460,7 @@ fetch_statentries_for_relation(Relation pg_statext, Oid relid)
ArrayType *arr;
char *enabled;
Form_pg_statistic_ext staForm;
+ List *exprs = NIL;
entry = palloc0(sizeof(StatExtEntry));
staForm = (Form_pg_statistic_ext) GETSTRUCT(htup);
@@ -415,10 +488,39 @@ fetch_statentries_for_relation(Relation pg_statext, Oid relid)
{
Assert((enabled[i] == STATS_EXT_NDISTINCT) ||
(enabled[i] == STATS_EXT_DEPENDENCIES) ||
- (enabled[i] == STATS_EXT_MCV));
+ (enabled[i] == STATS_EXT_MCV) ||
+ (enabled[i] == STATS_EXT_EXPRESSIONS));
entry->types = lappend_int(entry->types, (int) enabled[i]);
}
+ /* decode expression (if any) */
+ datum = SysCacheGetAttr(STATEXTOID, htup,
+ Anum_pg_statistic_ext_stxexprs, &isnull);
+
+ if (!isnull)
+ {
+ char *exprsString;
+
+ exprsString = TextDatumGetCString(datum);
+ exprs = (List *) stringToNode(exprsString);
+
+ pfree(exprsString);
+
+ /*
+ * Run the expressions through eval_const_expressions. This is not just an
+ * optimization, but is necessary, because the planner will be comparing
+ * them to similarly-processed qual clauses, and may fail to detect valid
+ * matches without this. We must not use canonicalize_qual, however,
+ * since these aren't qual expressions.
+ */
+ exprs = (List *) eval_const_expressions(NULL, (Node *) exprs);
+
+ /* May as well fix opfuncids too */
+ fix_opfuncids((Node *) exprs);
+ }
+
+ entry->exprs = exprs;
+
result = lappend(result, entry);
}
@@ -427,6 +529,86 @@ fetch_statentries_for_relation(Relation pg_statext, Oid relid)
return result;
}
+
+/*
+ * examine_attribute -- pre-analysis of a single column
+ *
+ * Determine whether the column is analyzable; if so, create and initialize
+ * a VacAttrStats struct for it. If not, return NULL.
+ */
+static VacAttrStats *
+examine_attribute(Node *expr)
+{
+ HeapTuple typtuple;
+ VacAttrStats *stats;
+ int i;
+ bool ok;
+
+ /*
+ * Create the VacAttrStats struct. Note that we only have a copy of the
+ * fixed fields of the pg_attribute tuple.
+ */
+ stats = (VacAttrStats *) palloc0(sizeof(VacAttrStats));
+
+ /* fake the attribute */
+ stats->attr = (Form_pg_attribute) palloc0(ATTRIBUTE_FIXED_PART_SIZE);
+ stats->attr->attstattarget = -1;
+
+ /*
+ * When analyzing an expression index, believe the expression tree's type
+ * not the column datatype --- the latter might be the opckeytype storage
+ * type of the opclass, which is not interesting for our purposes. (Note:
+ * if we did anything with non-expression index columns, we'd need to
+ * figure out where to get the correct type info from, but for now that's
+ * not a problem.) It's not clear whether anyone will care about the
+ * typmod, but we store that too just in case.
+ */
+ stats->attrtypid = exprType(expr);
+ stats->attrtypmod = exprTypmod(expr);
+ stats->attrcollid = exprCollation(expr);
+
+ typtuple = SearchSysCacheCopy1(TYPEOID,
+ ObjectIdGetDatum(stats->attrtypid));
+ if (!HeapTupleIsValid(typtuple))
+ elog(ERROR, "cache lookup failed for type %u", stats->attrtypid);
+ stats->attrtype = (Form_pg_type) GETSTRUCT(typtuple);
+ // stats->anl_context = anl_context; /* FIXME? */
+ stats->tupattnum = InvalidAttrNumber;
+
+ /*
+ * The fields describing the stats->stavalues[n] element types default to
+ * the type of the data being analyzed, but the type-specific typanalyze
+ * function can change them if it wants to store something else.
+ */
+ for (i = 0; i < STATISTIC_NUM_SLOTS; i++)
+ {
+ stats->statypid[i] = stats->attrtypid;
+ stats->statyplen[i] = stats->attrtype->typlen;
+ stats->statypbyval[i] = stats->attrtype->typbyval;
+ stats->statypalign[i] = stats->attrtype->typalign;
+ }
+
+ /*
+ * Call the type-specific typanalyze function. If none is specified, use
+ * std_typanalyze().
+ */
+ if (OidIsValid(stats->attrtype->typanalyze))
+ ok = DatumGetBool(OidFunctionCall1(stats->attrtype->typanalyze,
+ PointerGetDatum(stats)));
+ else
+ ok = std_typanalyze(stats);
+
+ if (!ok || stats->compute_stats == NULL || stats->minrows <= 0)
+ {
+ heap_freetuple(typtuple);
+ pfree(stats->attr);
+ pfree(stats);
+ return NULL;
+ }
+
+ return stats;
+}
+
/*
* Using 'vacatts' of size 'nvacatts' as input data, return a newly built
* VacAttrStats array which includes only the items corresponding to
@@ -435,15 +617,18 @@ fetch_statentries_for_relation(Relation pg_statext, Oid relid)
* to the caller that the stats should not be built.
*/
static VacAttrStats **
-lookup_var_attr_stats(Relation rel, Bitmapset *attrs,
+lookup_var_attr_stats(Relation rel, Bitmapset *attrs, List *exprs,
int nvacatts, VacAttrStats **vacatts)
{
int i = 0;
int x = -1;
+ int natts;
VacAttrStats **stats;
+ ListCell *lc;
- stats = (VacAttrStats **)
- palloc(bms_num_members(attrs) * sizeof(VacAttrStats *));
+ natts = bms_num_members(attrs) + list_length(exprs);
+
+ stats = (VacAttrStats **) palloc(natts * sizeof(VacAttrStats *));
/* lookup VacAttrStats info for the requested columns (same attnum) */
while ((x = bms_next_member(attrs, x)) >= 0)
@@ -480,6 +665,24 @@ lookup_var_attr_stats(Relation rel, Bitmapset *attrs,
i++;
}
+ /* also add info for expressions */
+ foreach (lc, exprs)
+ {
+ Node *expr = (Node *) lfirst(lc);
+
+ stats[i] = examine_attribute(expr);
+
+ /*
+ * FIXME We need tuple descriptor later, and we just grab it from
+ * stats[0]->tupDesc (see e.g. statext_mcv_build). But as coded
+ * examine_attribute does not set that, so just grab it from the
+ * first vacatts element.
+ */
+ stats[i]->tupDesc = vacatts[0]->tupDesc;
+
+ i++;
+ }
+
return stats;
}
@@ -491,7 +694,7 @@ lookup_var_attr_stats(Relation rel, Bitmapset *attrs,
static void
statext_store(Oid statOid,
MVNDistinct *ndistinct, MVDependencies *dependencies,
- MCVList *mcv, VacAttrStats **stats)
+ MCVList *mcv, Datum exprs, VacAttrStats **stats)
{
Relation pg_stextdata;
HeapTuple stup,
@@ -532,11 +735,17 @@ statext_store(Oid statOid,
nulls[Anum_pg_statistic_ext_data_stxdmcv - 1] = (data == NULL);
values[Anum_pg_statistic_ext_data_stxdmcv - 1] = PointerGetDatum(data);
}
+ if (exprs != (Datum) 0)
+ {
+ nulls[Anum_pg_statistic_ext_data_stxdexpr - 1] = false;
+ values[Anum_pg_statistic_ext_data_stxdexpr - 1] = exprs;
+ }
/* always replace the value (either by bytea or NULL) */
replaces[Anum_pg_statistic_ext_data_stxdndistinct - 1] = true;
replaces[Anum_pg_statistic_ext_data_stxddependencies - 1] = true;
replaces[Anum_pg_statistic_ext_data_stxdmcv - 1] = true;
+ replaces[Anum_pg_statistic_ext_data_stxdexpr - 1] = true;
/* there should already be a pg_statistic_ext_data tuple */
oldtup = SearchSysCache1(STATEXTDATASTXOID, ObjectIdGetDatum(statOid));
@@ -741,8 +950,9 @@ build_attnums_array(Bitmapset *attrs, int *numattrs)
* can simply pfree the return value to release all of it.
*/
SortItem *
-build_sorted_items(int numrows, int *nitems, HeapTuple *rows, TupleDesc tdesc,
- MultiSortSupport mss, int numattrs, AttrNumber *attnums)
+build_sorted_items(int numrows, int *nitems, HeapTuple *rows, ExprInfo *exprs,
+ TupleDesc tdesc, MultiSortSupport mss,
+ int numattrs, AttrNumber *attnums)
{
int i,
j,
@@ -789,8 +999,24 @@ build_sorted_items(int numrows, int *nitems, HeapTuple *rows, TupleDesc tdesc,
{
Datum value;
bool isnull;
+ int attlen;
+
+ if (attnums[j] <= MaxHeapAttributeNumber)
+ {
+ value = heap_getattr(rows[i], attnums[j], tdesc, &isnull);
+ attlen = TupleDescAttr(tdesc, attnums[j] - 1)->attlen;
+ }
+ else
+ {
+ int idx = EXPRESSION_INDEX(attnums[j]);
+
+ Assert((idx >= 0) && (idx < exprs->nexprs));
+
+ value = exprs->values[idx][i];
+ isnull = exprs->nulls[idx][i];
- value = heap_getattr(rows[i], attnums[j], tdesc, &isnull);
+ attlen = get_typlen(exprs->types[idx]);
+ }
/*
* If this is a varlena value, check if it's too wide and if yes
@@ -801,8 +1027,7 @@ build_sorted_items(int numrows, int *nitems, HeapTuple *rows, TupleDesc tdesc,
* on the assumption that those are small (below WIDTH_THRESHOLD)
* and will be discarded at the end of analyze.
*/
- if ((!isnull) &&
- (TupleDescAttr(tdesc, attnums[j] - 1)->attlen == -1))
+ if ((!isnull) && (attlen == -1))
{
if (toast_raw_datum_size(value) > WIDTH_THRESHOLD)
{
@@ -881,7 +1106,8 @@ has_stats_of_kind(List *stats, char requiredkind)
*/
StatisticExtInfo *
choose_best_statistics(List *stats, char requiredkind,
- Bitmapset **clause_attnums, int nclauses)
+ Bitmapset **clause_attnums, List **clause_exprs,
+ int nclauses)
{
ListCell *lc;
StatisticExtInfo *best_match = NULL;
@@ -894,6 +1120,7 @@ choose_best_statistics(List *stats, char requiredkind,
StatisticExtInfo *info = (StatisticExtInfo *) lfirst(lc);
Bitmapset *matched = NULL;
int num_matched;
+ int num_matched_exprs;
int numkeys;
/* skip statistics that are not of the correct type */
@@ -920,6 +1147,38 @@ choose_best_statistics(List *stats, char requiredkind,
num_matched = bms_num_members(matched);
bms_free(matched);
+ /*
+ * Collect expressions in remaining (unestimated) expressions, covered
+ * by an expression in this statistic object.
+ */
+ num_matched_exprs = 0;
+ for (i = 0; i < nclauses; i++)
+ {
+ ListCell *lc3;
+
+ /* ignore incompatible/estimated expressions */
+ if (!clause_exprs[i])
+ continue;
+
+ /* ignore expressions that are not covered by this object */
+ foreach (lc3, clause_exprs[i])
+ {
+ ListCell *lc2;
+ Node *expr = (Node *) lfirst(lc3);
+
+ foreach(lc2, info->exprs)
+ {
+ Node *stat_expr = (Node *) lfirst(lc2);
+
+ if (equal(expr, stat_expr))
+ {
+ num_matched_exprs++;
+ break;
+ }
+ }
+ }
+ }
+
/*
* save the actual number of keys in the stats so that we can choose
* the narrowest stats with the most matching keys.
@@ -931,11 +1190,12 @@ choose_best_statistics(List *stats, char requiredkind,
* when it matches the same number of attributes but these stats have
* fewer keys than any previous match.
*/
- if (num_matched > best_num_matched ||
- (num_matched == best_num_matched && numkeys < best_match_keys))
+ if (num_matched + num_matched_exprs > best_num_matched ||
+ ((num_matched + num_matched_exprs) == best_num_matched &&
+ numkeys < best_match_keys))
{
best_match = info;
- best_num_matched = num_matched;
+ best_num_matched = num_matched + num_matched_exprs;
best_match_keys = numkeys;
}
}
@@ -994,7 +1254,7 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
return false;
/* Check if the expression has the right shape (one Var, one Const) */
- if (!examine_clause_args(expr->args, &var, NULL, NULL))
+ if (!examine_opclause_expression(expr, &var, NULL, NULL))
return false;
/*
@@ -1150,6 +1410,214 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
return false;
}
+/*
+ * statext_extract_expression_internal
+ * Extract parts of an expressions to match against extended stats.
+ *
+ * Given an expression, decompose it into "parts" that will be analyzed and
+ * matched against extended statistics. If the expression is not considered
+ * compatible (supported by extended statistics), this returns NIL.
+ *
+ * There's a certain amount of ambiguity, because some expressions may be
+ * split into parts in multiple ways. For example, consider expression
+ *
+ * (a + b) = 1
+ *
+ * which may be either considered as a single boolean expression, or it may
+ * be split into expression (a + b) and a constant. So this might return
+ * either ((a+b)=1) or (a+b) as valid expressions, but this does affect
+ * matching to extended statistics, because the expressions have to match
+ * the definition exactly. So ((a+b)=1) would match statistics defined as
+ *
+ * CREATE STATISTICS s ON ((a+b) = 1) FROM t;
+ *
+ * but not
+ *
+ * CREATE STATISTICS s ON (a+b) FROM t;
+ *
+ * which might be a bit confusing. We might enhance this to track those
+ * alternative decompositions somehow, and then modify the matching to
+ * extended statistics. But it seems non-trivial, because the AND/OR
+ * clauses make it "recursive".
+ *
+ * in which expressions might be extracted.
+ */
+static List *
+statext_extract_expression_internal(PlannerInfo *root, Node *clause, Index relid)
+{
+ /* Look inside any binary-compatible relabeling (as in examine_variable) */
+ if (IsA(clause, RelabelType))
+ clause = (Node *) ((RelabelType *) clause)->arg;
+
+ /* plain Var references (boolean Vars or recursive checks) */
+ if (IsA(clause, Var))
+ {
+ Var *var = (Var *) clause;
+
+ /* Ensure var is from the correct relation */
+ if (var->varno != relid)
+ return NIL;
+
+ /* we also better ensure the Var is from the current level */
+ if (var->varlevelsup > 0)
+ return NIL;
+
+ /* Also skip system attributes (we don't allow stats on those). */
+ if (!AttrNumberIsForUserDefinedAttr(var->varattno))
+ return NIL;
+
+ return list_make1(clause);
+ }
+
+ /* (Var op Const) or (Const op Var) */
+ if (is_opclause(clause))
+ {
+ RangeTblEntry *rte = root->simple_rte_array[relid];
+ OpExpr *expr = (OpExpr *) clause;
+ Node *expr2 = NULL;
+
+ /* Only expressions with two arguments are considered compatible. */
+ if (list_length(expr->args) != 2)
+ return NIL;
+
+ /* Check if the expression has the right shape (one Expr, one Const) */
+ if (!examine_opclause_expression2(expr, &expr2, NULL, NULL))
+ return NIL;
+
+ /*
+ * If it's not one of the supported operators ("=", "<", ">", etc.),
+ * just ignore the clause, as it's not compatible with MCV lists.
+ *
+ * This uses the function for estimating selectivity, not the operator
+ * directly (a bit awkward, but well ...).
+ */
+ switch (get_oprrest(expr->opno))
+ {
+ case F_EQSEL:
+ case F_NEQSEL:
+ case F_SCALARLTSEL:
+ case F_SCALARLESEL:
+ case F_SCALARGTSEL:
+ case F_SCALARGESEL:
+ /* supported, will continue with inspection of the Var */
+ break;
+
+ default:
+ /* other estimators are considered unknown/unsupported */
+ return NIL;
+ }
+
+ /*
+ * If there are any securityQuals on the RTE from security barrier
+ * views or RLS policies, then the user may not have access to all the
+ * table's data, and we must check that the operator is leak-proof.
+ *
+ * If the operator is leaky, then we must ignore this clause for the
+ * purposes of estimating with MCV lists, otherwise the operator might
+ * reveal values from the MCV list that the user doesn't have
+ * permission to see.
+ */
+ if (rte->securityQuals != NIL &&
+ !get_func_leakproof(get_opcode(expr->opno)))
+ return NIL;
+
+ return list_make1(expr2);
+ }
+
+ if (IsA(clause, ScalarArrayOpExpr))
+ {
+ RangeTblEntry *rte = root->simple_rte_array[relid];
+ ScalarArrayOpExpr *expr = (ScalarArrayOpExpr *) clause;
+ Node *expr2 = NULL;
+
+ /* Only expressions with two arguments are considered compatible. */
+ if (list_length(expr->args) != 2)
+ return NIL;
+
+ /* Check if the expression has the right shape (one Expr, one Const) */
+ if (!examine_clause_args2(expr->args, &expr2, NULL, NULL))
+ return NIL;
+
+ /*
+ * If there are any securityQuals on the RTE from security barrier
+ * views or RLS policies, then the user may not have access to all the
+ * table's data, and we must check that the operator is leak-proof.
+ *
+ * If the operator is leaky, then we must ignore this clause for the
+ * purposes of estimating with MCV lists, otherwise the operator might
+ * reveal values from the MCV list that the user doesn't have
+ * permission to see.
+ */
+ if (rte->securityQuals != NIL &&
+ !get_func_leakproof(get_opcode(expr->opno)))
+ return NIL;
+
+ return list_make1(expr2);
+ }
+
+ /* AND/OR/NOT clause */
+ if (is_andclause(clause) ||
+ is_orclause(clause) ||
+ is_notclause(clause))
+ {
+ /*
+ * AND/OR/NOT-clauses are supported if all sub-clauses are supported
+ *
+ * Perhaps we could improve this by handling mixed cases, when some of
+ * the clauses are supported and some are not. Selectivity for the
+ * supported subclauses would be computed using extended statistics,
+ * and the remaining clauses would be estimated using the traditional
+ * algorithm (product of selectivities).
+ *
+ * It however seems overly complex, and in a way we already do that
+ * because if we reject the whole clause as unsupported here, it will
+ * be eventually passed to clauselist_selectivity() which does exactly
+ * this (split into supported/unsupported clauses etc).
+ */
+ BoolExpr *expr = (BoolExpr *) clause;
+ ListCell *lc;
+ List *exprs = NIL;
+
+ foreach(lc, expr->args)
+ {
+ List *tmp;
+
+ /*
+ * Had we found incompatible clause in the arguments, treat the
+ * whole clause as incompatible.
+ */
+ tmp = statext_extract_expression_internal(root,
+ (Node *) lfirst(lc),
+ relid);
+
+ if (!tmp)
+ return NIL;
+
+ exprs = list_concat(exprs, tmp);
+ }
+
+ return exprs;
+ }
+
+ /* Var IS NULL */
+ if (IsA(clause, NullTest))
+ {
+ NullTest *nt = (NullTest *) clause;
+
+ /*
+ * Only simple (Var IS NULL) expressions supported for now. Maybe we
+ * could use examine_variable to fix this?
+ */
+ if (!IsA(nt->arg, Var))
+ return NIL;
+
+ return statext_extract_expression_internal(root, (Node *) (nt->arg),
+ relid);
+ }
+
+ return NIL;
+}
+
/*
* statext_is_compatible_clause
* Determines if the clause is compatible with MCV lists.
@@ -1163,6 +1631,8 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
*
* (c) combinations using AND/OR/NOT
*
+ * (d) ScalarArrayOpExprs of the form (Var op ANY (array)) or (Var op ALL (array))
+ *
* In the future, the range of supported clauses may be expanded to more
* complex cases, for example (Var op Var).
*/
@@ -1249,6 +1719,101 @@ statext_is_compatible_clause(PlannerInfo *root, Node *clause, Index relid,
return true;
}
+/*
+ * statext_extract_expression
+ * Determines if the clause is compatible with extended statistics.
+ *
+ * Currently, we only support three types of clauses:
+ *
+ * (a) OpExprs of the form (Var op Const), or (Const op Var), where the op
+ * is one of ("=", "<", ">", ">=", "<=")
+ *
+ * (b) (Var IS [NOT] NULL)
+ *
+ * (c) combinations using AND/OR/NOT
+ *
+ * (d) ScalarArrayOpExprs of the form (Var op ANY (array)) or (Var op ALL (array))
+ *
+ * In the future, the range of supported clauses may be expanded to more
+ * complex cases, for example (Var op Var).
+ */
+static List *
+statext_extract_expression(PlannerInfo *root, Node *clause, Index relid)
+{
+ RestrictInfo *rinfo = (RestrictInfo *) clause;
+ RangeTblEntry *rte = root->simple_rte_array[relid];
+ List *exprs;
+ Oid userid;
+
+ if (!IsA(rinfo, RestrictInfo))
+ return NIL;
+
+ /* Pseudoconstants are not really interesting here. */
+ if (rinfo->pseudoconstant)
+ return NIL;
+
+ /* clauses referencing multiple varnos are incompatible */
+ if (bms_membership(rinfo->clause_relids) != BMS_SINGLETON)
+ return NIL;
+
+ /* Check the clause and extract expressions it's composed of. */
+ exprs = statext_extract_expression_internal(root, (Node *) rinfo->clause, relid);
+
+ /*
+ * If there are no potentially interesting expressions (supported by
+ * extended statistics), we're done;
+ */
+ if (!exprs)
+ return NIL;
+
+ /*
+ * Check that the user has permission to read all these attributes. Use
+ * checkAsUser if it's set, in case we're accessing the table via a view.
+ */
+ userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
+
+ if (pg_class_aclcheck(rte->relid, userid, ACL_SELECT) != ACLCHECK_OK)
+ {
+ Bitmapset *attnums = NULL;
+
+ /* Extract all attribute numbers from the expressions. */
+ pull_varattnos((Node *) exprs, relid, &attnums);
+
+ /* Don't have table privilege, must check individual columns */
+ if (bms_is_member(InvalidAttrNumber, attnums))
+ {
+ /* Have a whole-row reference, must have access to all columns */
+ if (pg_attribute_aclcheck_all(rte->relid, userid, ACL_SELECT,
+ ACLMASK_ALL) != ACLCHECK_OK)
+ return NIL;
+ }
+ else
+ {
+ /* Check the columns referenced by the clause */
+ int attnum = -1;
+
+ while ((attnum = bms_next_member(attnums, attnum)) >= 0)
+ {
+ AttrNumber tmp;
+
+ /* Adjust for system attributes (offset for bitmap). */
+ tmp = attnum + FirstLowInvalidHeapAttributeNumber;
+
+ /* Ignore system attributes, those can't have statistics. */
+ if (!AttrNumberIsForUserDefinedAttr(tmp))
+ return NIL;
+
+ if (pg_attribute_aclcheck(rte->relid, tmp, userid,
+ ACL_SELECT) != ACLCHECK_OK)
+ return NIL;
+ }
+ }
+ }
+
+ /* If we reach here, the clause is OK */
+ return exprs;
+}
+
/*
* statext_mcv_clauselist_selectivity
* Estimate clauses using the best multi-column statistics.
@@ -1290,7 +1855,8 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli
bool is_or)
{
ListCell *l;
- Bitmapset **list_attnums;
+ Bitmapset **list_attnums; /* attnums extracted from the clause */
+ List **list_exprs; /* expressions matched to any statistic */
int listidx;
Selectivity sel = (is_or) ? 0.0 : 1.0;
@@ -1301,6 +1867,9 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli
list_attnums = (Bitmapset **) palloc(sizeof(Bitmapset *) *
list_length(clauses));
+ /* expressions extracted from complex expressions */
+ list_exprs = (List **) palloc(sizeof(Node *) * list_length(clauses));
+
/*
* Pre-process the clauses list to extract the attnums seen in each item.
* We need to determine if there's any clauses which will be useful for
@@ -1318,11 +1887,100 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli
Node *clause = (Node *) lfirst(l);
Bitmapset *attnums = NULL;
+ /* the clause is considered incompatible by default */
+ list_attnums[listidx] = NULL;
+
+ /* and it's also not covered exactly by the statistic */
+ list_exprs[listidx] = NULL;
+
+ /*
+ * First see if the clause is simple enough to be covered directly
+ * by the attributes. If not, see if there's at least one statistic
+ * object using the expression as-is.
+ */
if (!bms_is_member(listidx, *estimatedclauses) &&
statext_is_compatible_clause(root, clause, rel->relid, &attnums))
+ {
+ /* simple expression, covered through attnum(s) */
list_attnums[listidx] = attnums;
+ }
else
- list_attnums[listidx] = NULL;
+ {
+ ListCell *lc;
+ List *exprs;
+
+ /*
+ * XXX This is kinda dubious, because we extract the smallest
+ * clauses - e.g. from (Var op Const) we extract Var. But maybe
+ * the statistics covers larger expressions, so maybe this will
+ * skip that. For example give ((a+b) + (c+d)) it's not clear
+ * if we should extract the whole clause or some smaller parts.
+ * OTOH we need (Expr op Const) so maybe we only care about the
+ * clause as a whole?
+ */
+ exprs = statext_extract_expression(root, clause, rel->relid);
+
+ /* complex expression, search for statistic covering all parts */
+ foreach(lc, rel->statlist)
+ {
+ ListCell *le;
+ StatisticExtInfo *info = (StatisticExtInfo *) lfirst(lc);
+
+ /*
+ * Assume all parts are covered by this statistics, we'll
+ * stop if we found part that is not covered.
+ */
+ bool covered = true;
+
+ /* have we already matched the expression to a statistic? */
+ Assert(!list_exprs[listidx]);
+
+ /* no expressions in the statistic */
+ if (!info->exprs)
+ continue;
+
+ foreach(le, exprs)
+ {
+ ListCell *lc2;
+ Node *expr = (Node *) lfirst(le);
+ bool found = false;
+
+ /*
+ * Walk the expressions, see if all expressions extracted from
+ * the clause are covered by the extended statistic object.
+ */
+ foreach (lc2, info->exprs)
+ {
+ Node *stat_expr = (Node *) lfirst(lc2);
+
+ if (equal(expr, stat_expr))
+ {
+ found = true;
+ break;
+ }
+ }
+
+ /* found expression not covered by the statistics, stop */
+ if (!found)
+ {
+ covered = false;
+ break;
+ }
+ }
+
+ /*
+ * OK, we found a statistics covering this clause, stop looking
+ * for another one
+ */
+ if (covered)
+ {
+ /* XXX should this add the original expression instead? */
+ list_exprs[listidx] = exprs;
+ break;
+ }
+
+ }
+ }
listidx++;
}
@@ -1336,7 +1994,8 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli
/* find the best suited statistics object for these attnums */
stat = choose_best_statistics(rel->statlist, STATS_EXT_MCV,
- list_attnums, list_length(clauses));
+ list_attnums, list_exprs,
+ list_length(clauses));
/*
* if no (additional) matching stats could be found then we've nothing
@@ -1359,11 +2018,13 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli
{
/*
* If the clause is compatible with the selected statistics, mark
- * it as estimated and add it to the list to estimate.
+ * it as estimated and add it to the list to estimate. It may be
+ * either a simple clause, or an expression.
*/
if (list_attnums[listidx] != NULL &&
bms_is_subset(list_attnums[listidx], stat->keys))
{
+ /* simple clause (single Var) */
if (bms_membership(list_attnums[listidx]) == BMS_SINGLETON)
simple_clauses = bms_add_member(simple_clauses,
list_length(stat_clauses));
@@ -1374,6 +2035,45 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli
bms_free(list_attnums[listidx]);
list_attnums[listidx] = NULL;
}
+ else if (list_exprs[listidx] != NIL)
+ {
+ /* are all parts of the expression covered by the statistic? */
+ ListCell *lc;
+ int ncovered = 0;
+
+ foreach (lc, list_exprs[listidx])
+ {
+ ListCell *lc2;
+ Node *expr = (Node *) lfirst(lc);
+ bool found = false;
+
+ foreach (lc2, stat->exprs)
+ {
+ Node *stat_expr = (Node *) lfirst(lc2);
+
+ if (equal(expr, stat_expr))
+ {
+ found = true;
+ break;
+ }
+ }
+
+ /* count it as covered and continue to the next expression */
+ if (found)
+ ncovered++;
+ }
+
+ /* all parts of the expression are covered by this statistics */
+ if (ncovered == list_length(list_exprs[listidx]))
+ {
+ stat_clauses = lappend(stat_clauses, (Node *) lfirst(l));
+ *estimatedclauses = bms_add_member(*estimatedclauses, listidx);
+
+ // bms_free(list_attnums[listidx]);
+ list_exprs[listidx] = NULL;
+ }
+
+ }
listidx++;
}
@@ -1621,3 +2321,788 @@ examine_clause_args(List *args, Var **varp, Const **cstp, bool *varonleftp)
return true;
}
+
+bool
+examine_clause_args2(List *args, Node **exprp, Const **cstp, bool *expronleftp)
+{
+ Node *expr;
+ Const *cst;
+ bool expronleft;
+ Node *leftop,
+ *rightop;
+
+ /* enforced by statext_is_compatible_clause_internal */
+ Assert(list_length(args) == 2);
+
+ leftop = linitial(args);
+ rightop = lsecond(args);
+
+ /* strip RelabelType from either side of the expression */
+ if (IsA(leftop, RelabelType))
+ leftop = (Node *) ((RelabelType *) leftop)->arg;
+
+ if (IsA(rightop, RelabelType))
+ rightop = (Node *) ((RelabelType *) rightop)->arg;
+
+ if (IsA(rightop, Const))
+ {
+ expr = (Node *) leftop;
+ cst = (Const *) rightop;
+ expronleft = true;
+ }
+ else if (IsA(leftop, Const))
+ {
+ expr = (Node *) rightop;
+ cst = (Const *) leftop;
+ expronleft = false;
+ }
+ else
+ return false;
+
+ /* return pointers to the extracted parts if requested */
+ if (exprp)
+ *exprp = expr;
+
+ if (cstp)
+ *cstp = cst;
+
+ if (expronleftp)
+ *expronleftp = expronleft;
+
+ return true;
+}
+
+bool
+examine_opclause_expression(OpExpr *expr, Var **varp, Const **cstp, bool *varonleftp)
+{
+ Var *var;
+ Const *cst;
+ bool varonleft;
+ Node *leftop,
+ *rightop;
+
+ /* enforced by statext_is_compatible_clause_internal */
+ Assert(list_length(expr->args) == 2);
+
+ leftop = linitial(expr->args);
+ rightop = lsecond(expr->args);
+
+ /* strip RelabelType from either side of the expression */
+ if (IsA(leftop, RelabelType))
+ leftop = (Node *) ((RelabelType *) leftop)->arg;
+
+ if (IsA(rightop, RelabelType))
+ rightop = (Node *) ((RelabelType *) rightop)->arg;
+
+ if (IsA(leftop, Var) && IsA(rightop, Const))
+ {
+ var = (Var *) leftop;
+ cst = (Const *) rightop;
+ varonleft = true;
+ }
+ else if (IsA(leftop, Const) && IsA(rightop, Var))
+ {
+ var = (Var *) rightop;
+ cst = (Const *) leftop;
+ varonleft = false;
+ }
+ else
+ return false;
+
+ /* return pointers to the extracted parts if requested */
+ if (varp)
+ *varp = var;
+
+ if (cstp)
+ *cstp = cst;
+
+ if (varonleftp)
+ *varonleftp = varonleft;
+
+ return true;
+}
+
+bool
+examine_opclause_expression2(OpExpr *expr, Node **exprp, Const **cstp, bool *expronleftp)
+{
+ Node *expr2;
+ Const *cst;
+ bool expronleft;
+ Node *leftop,
+ *rightop;
+
+ /* enforced by statext_is_compatible_clause_internal */
+ Assert(list_length(expr->args) == 2);
+
+ leftop = linitial(expr->args);
+ rightop = lsecond(expr->args);
+
+ /* strip RelabelType from either side of the expression */
+ if (IsA(leftop, RelabelType))
+ leftop = (Node *) ((RelabelType *) leftop)->arg;
+
+ if (IsA(rightop, RelabelType))
+ rightop = (Node *) ((RelabelType *) rightop)->arg;
+
+ if (IsA(rightop, Const))
+ {
+ expr2 = (Node *) leftop;
+ cst = (Const *) rightop;
+ expronleft = true;
+ }
+ else if (IsA(leftop, Const))
+ {
+ expr2 = (Node *) rightop;
+ cst = (Const *) leftop;
+ expronleft = false;
+ }
+ else
+ return false;
+
+ /* return pointers to the extracted parts if requested */
+ if (exprp)
+ *exprp = expr2;
+
+ if (cstp)
+ *cstp = cst;
+
+ if (expronleftp)
+ *expronleftp = expronleft;
+
+ return true;
+}
+
+
+/*
+ * Compute statistics about expressions of a relation.
+ */
+static void
+compute_expr_stats(Relation onerel, double totalrows,
+ AnlExprData *exprdata, int nexprs,
+ HeapTuple *rows, int numrows)
+{
+ MemoryContext expr_context,
+ old_context;
+ int ind,
+ i;
+
+ expr_context = AllocSetContextCreate(CurrentMemoryContext,
+ "Analyze Expression",
+ ALLOCSET_DEFAULT_SIZES);
+ old_context = MemoryContextSwitchTo(expr_context);
+
+ for (ind = 0; ind < nexprs; ind++)
+ {
+ AnlExprData *thisdata = &exprdata[ind];
+ VacAttrStats *stats = thisdata->vacattrstat;
+ Node *expr = thisdata->expr;
+ TupleTableSlot *slot;
+ EState *estate;
+ ExprContext *econtext;
+ Datum *exprvals;
+ bool *exprnulls;
+ ExprState *exprstate;
+ int tcnt;
+
+ /* Are we still in the main context? */
+ Assert(CurrentMemoryContext == expr_context);
+
+ /*
+ * Need an EState for evaluation of expressions. Create it in
+ * the per-expression context to be sure it gets cleaned up at
+ * the bottom of the loop.
+ */
+ estate = CreateExecutorState();
+ econtext = GetPerTupleExprContext(estate);
+
+ /* Set up expression evaluation state */
+ exprstate = ExecPrepareExpr((Expr *) expr, estate);
+
+ /* Need a slot to hold the current heap tuple, too */
+ slot = MakeSingleTupleTableSlot(RelationGetDescr(onerel),
+ &TTSOpsHeapTuple);
+
+ /* Arrange for econtext's scan tuple to be the tuple under test */
+ econtext->ecxt_scantuple = slot;
+
+ /* Compute and save index expression values */
+ exprvals = (Datum *) palloc(numrows * sizeof(Datum));
+ exprnulls = (bool *) palloc(numrows * sizeof(bool));
+
+ tcnt = 0;
+ for (i = 0; i < numrows; i++)
+ {
+ Datum datum;
+ bool isnull;
+
+ /*
+ * Reset the per-tuple context each time, to reclaim any cruft
+ * left behind by evaluating the predicate or index expressions.
+ */
+ ResetExprContext(econtext);
+
+ /* Set up for expression evaluation */
+ ExecStoreHeapTuple(rows[i], slot, false);
+
+ /*
+ * Evaluate the expression. We do this in the per-tuple context
+ * so as not to leak memory, and then copy the result into the
+ * context created at the beginning of this function.
+ */
+ datum = ExecEvalExprSwitchContext(exprstate,
+ GetPerTupleExprContext(estate),
+ &isnull);
+ if (isnull)
+ {
+ exprvals[tcnt] = (Datum) 0;
+ exprnulls[tcnt] = true;
+ }
+ else
+ {
+ /* Make sure we copy the data into the context. */
+ Assert(CurrentMemoryContext == expr_context);
+
+ exprvals[tcnt] = datumCopy(datum,
+ stats->attrtype->typbyval,
+ stats->attrtype->typlen);
+ exprnulls[tcnt] = false;
+ }
+
+ tcnt++;
+ }
+
+ /*
+ * Now we can compute the statistics for the expression columns.
+ *
+ * XXX Unlike compute_index_stats we don't need to switch and reset
+ * memory contexts here, because we're only computing stats for a
+ * single expression (and not iterating over many indexes), so we
+ * just do it in expr_context. Note that compute_stats copies the
+ * result into stats->anl_context, so it does not disappear.
+ */
+ if (tcnt > 0)
+ {
+ AttributeOpts *aopt =
+ get_attribute_options(stats->attr->attrelid,
+ stats->attr->attnum);
+
+ stats->exprvals = exprvals;
+ stats->exprnulls = exprnulls;
+ stats->rowstride = 1;
+ stats->compute_stats(stats,
+ expr_fetch_func,
+ tcnt,
+ tcnt);
+
+ /*
+ * If the n_distinct option is specified, it overrides the
+ * above computation.
+ */
+ if (aopt != NULL && aopt->n_distinct != 0.0)
+ stats->stadistinct = aopt->n_distinct;
+ }
+
+ /* And clean up */
+ MemoryContextSwitchTo(expr_context);
+
+ ExecDropSingleTupleTableSlot(slot);
+ FreeExecutorState(estate);
+ MemoryContextResetAndDeleteChildren(expr_context);
+ }
+
+ MemoryContextSwitchTo(old_context);
+ MemoryContextDelete(expr_context);
+}
+
+
+/*
+ * Fetch function for analyzing index expressions.
+ *
+ * We have not bothered to construct index tuples, instead the data is
+ * just in Datum arrays.
+ */
+static Datum
+expr_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull)
+{
+ int i;
+
+ /* exprvals and exprnulls are already offset for proper column */
+ i = rownum * stats->rowstride;
+ *isNull = stats->exprnulls[i];
+ return stats->exprvals[i];
+}
+
+/*
+ * Build analyze data for a list of expressions. As this is not tied
+ * directly to a relation (table or index), we have to fake some of
+ * the data.
+ */
+static AnlExprData *
+build_expr_data(List *exprs)
+{
+ int idx;
+ int nexprs = list_length(exprs);
+ AnlExprData *exprdata;
+ ListCell *lc;
+
+ exprdata = (AnlExprData *) palloc0(nexprs * sizeof(AnlExprData));
+
+ idx = 0;
+ foreach (lc, exprs)
+ {
+ Node *expr = (Node *) lfirst(lc);
+ AnlExprData *thisdata = &exprdata[idx];
+
+ thisdata->expr = expr;
+ thisdata->vacattrstat = (VacAttrStats *) palloc(sizeof(VacAttrStats));
+
+ thisdata->vacattrstat = examine_expression(expr);
+ idx++;
+ }
+
+ return exprdata;
+}
+
+/*
+ * examine_expression -- pre-analysis of a single column
+ *
+ * Determine whether the column is analyzable; if so, create and initialize
+ * a VacAttrStats struct for it. If not, return NULL.
+ */
+static VacAttrStats *
+examine_expression(Node *expr)
+{
+ HeapTuple typtuple;
+ VacAttrStats *stats;
+ int i;
+ bool ok;
+
+ Assert(expr != NULL);
+
+ /*
+ * Create the VacAttrStats struct.
+ */
+ stats = (VacAttrStats *) palloc0(sizeof(VacAttrStats));
+
+ /*
+ * When analyzing an expression, believe the expression tree's type.
+ */
+ stats->attrtypid = exprType(expr);
+ stats->attrtypmod = exprTypmod(expr);
+
+ /*
+ * XXX Do we need to do anything special about the collation, similar
+ * to what examine_attribute does for expression indexes?
+ */
+ stats->attrcollid = exprCollation(expr);
+
+ /*
+ * We don't have any pg_attribute for expressions, so let's fake
+ * something reasonable into attstattarget, which is the only thing
+ * std_typanalyze needs.
+ */
+ stats->attr = (Form_pg_attribute) palloc(ATTRIBUTE_FIXED_PART_SIZE);
+
+ /*
+ * FIXME we should probably get the target from the extended stats
+ * object, or something like that.
+ */
+ stats->attr->attstattarget = default_statistics_target;
+
+ /* initialize some basic fields */
+ stats->attr->attrelid = InvalidOid;
+ stats->attr->attnum = InvalidAttrNumber;
+ stats->attr->atttypid = stats->attrtypid;
+
+ typtuple = SearchSysCacheCopy1(TYPEOID,
+ ObjectIdGetDatum(stats->attrtypid));
+ if (!HeapTupleIsValid(typtuple))
+ elog(ERROR, "cache lookup failed for type %u", stats->attrtypid);
+ stats->attrtype = (Form_pg_type) GETSTRUCT(typtuple);
+ stats->anl_context = CurrentMemoryContext; /* XXX should be using something else? */
+ stats->tupattnum = InvalidAttrNumber;
+
+ /*
+ * The fields describing the stats->stavalues[n] element types default to
+ * the type of the data being analyzed, but the type-specific typanalyze
+ * function can change them if it wants to store something else.
+ */
+ for (i = 0; i < STATISTIC_NUM_SLOTS; i++)
+ {
+ stats->statypid[i] = stats->attrtypid;
+ stats->statyplen[i] = stats->attrtype->typlen;
+ stats->statypbyval[i] = stats->attrtype->typbyval;
+ stats->statypalign[i] = stats->attrtype->typalign;
+ }
+
+ /*
+ * Call the type-specific typanalyze function. If none is specified, use
+ * std_typanalyze().
+ */
+ if (OidIsValid(stats->attrtype->typanalyze))
+ ok = DatumGetBool(OidFunctionCall1(stats->attrtype->typanalyze,
+ PointerGetDatum(stats)));
+ else
+ ok = std_typanalyze(stats);
+
+ if (!ok || stats->compute_stats == NULL || stats->minrows <= 0)
+ {
+ heap_freetuple(typtuple);
+ pfree(stats);
+ return NULL;
+ }
+
+ return stats;
+}
+
+/* form an array of pg_statistic rows (per update_attstats) */
+static Datum
+serialize_expr_stats(AnlExprData *exprdata, int nexprs)
+{
+ int exprno;
+ Oid typOid;
+ Relation sd;
+
+ ArrayBuildState *astate = NULL;
+
+ sd = table_open(StatisticRelationId, RowExclusiveLock);
+
+ /* lookup OID of composite type for pg_statistic */
+ typOid = get_rel_type_id(StatisticRelationId);
+ if (!OidIsValid(typOid))
+ ereport(ERROR,
+ (errcode(ERRCODE_WRONG_OBJECT_TYPE),
+ errmsg("relation \"pg_statistic\" does not have a composite type")));
+
+ for (exprno = 0; exprno < nexprs; exprno++)
+ {
+ int i, k;
+ VacAttrStats *stats = exprdata[exprno].vacattrstat;
+
+ Datum values[Natts_pg_statistic];
+ bool nulls[Natts_pg_statistic];
+ HeapTuple stup;
+
+ if (!stats->stats_valid)
+ {
+ astate = accumArrayResult(astate,
+ (Datum) 0,
+ true,
+ typOid,
+ CurrentMemoryContext);
+ continue;
+ }
+
+ /*
+ * Construct a new pg_statistic tuple
+ */
+ for (i = 0; i < Natts_pg_statistic; ++i)
+ {
+ nulls[i] = false;
+ }
+
+ values[Anum_pg_statistic_starelid - 1] = ObjectIdGetDatum(InvalidOid);
+ values[Anum_pg_statistic_staattnum - 1] = Int16GetDatum(InvalidAttrNumber);
+ values[Anum_pg_statistic_stainherit - 1] = BoolGetDatum(false);
+ values[Anum_pg_statistic_stanullfrac - 1] = Float4GetDatum(stats->stanullfrac);
+ values[Anum_pg_statistic_stawidth - 1] = Int32GetDatum(stats->stawidth);
+ values[Anum_pg_statistic_stadistinct - 1] = Float4GetDatum(stats->stadistinct);
+ i = Anum_pg_statistic_stakind1 - 1;
+ for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
+ {
+ values[i++] = Int16GetDatum(stats->stakind[k]); /* stakindN */
+ }
+ i = Anum_pg_statistic_staop1 - 1;
+ for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
+ {
+ values[i++] = ObjectIdGetDatum(stats->staop[k]); /* staopN */
+ }
+ i = Anum_pg_statistic_stacoll1 - 1;
+ for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
+ {
+ values[i++] = ObjectIdGetDatum(stats->stacoll[k]); /* stacollN */
+ }
+ i = Anum_pg_statistic_stanumbers1 - 1;
+ for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
+ {
+ int nnum = stats->numnumbers[k];
+
+ if (nnum > 0)
+ {
+ int n;
+ Datum *numdatums = (Datum *) palloc(nnum * sizeof(Datum));
+ ArrayType *arry;
+
+ for (n = 0; n < nnum; n++)
+ numdatums[n] = Float4GetDatum(stats->stanumbers[k][n]);
+ /* XXX knows more than it should about type float4: */
+ arry = construct_array(numdatums, nnum,
+ FLOAT4OID,
+ sizeof(float4), true, TYPALIGN_INT);
+ values[i++] = PointerGetDatum(arry); /* stanumbersN */
+ }
+ else
+ {
+ nulls[i] = true;
+ values[i++] = (Datum) 0;
+ }
+ }
+ i = Anum_pg_statistic_stavalues1 - 1;
+ for (k = 0; k < STATISTIC_NUM_SLOTS; k++)
+ {
+ if (stats->numvalues[k] > 0)
+ {
+ ArrayType *arry;
+
+ arry = construct_array(stats->stavalues[k],
+ stats->numvalues[k],
+ stats->statypid[k],
+ stats->statyplen[k],
+ stats->statypbyval[k],
+ stats->statypalign[k]);
+ values[i++] = PointerGetDatum(arry); /* stavaluesN */
+ }
+ else
+ {
+ nulls[i] = true;
+ values[i++] = (Datum) 0;
+ }
+ }
+
+ stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
+
+ astate = accumArrayResult(astate,
+ heap_copy_tuple_as_datum(stup, RelationGetDescr(sd)),
+ false,
+ typOid,
+ CurrentMemoryContext);
+ }
+
+ table_close(sd, RowExclusiveLock);
+
+ return makeArrayResult(astate, CurrentMemoryContext);
+}
+
+
+/*
+ * Loads pg_statistic record from expression statistics for expression
+ * identified by the supplied index.
+ */
+HeapTuple
+statext_expressions_load(Oid stxoid, int idx)
+{
+ bool isnull;
+ Datum value;
+ HeapTuple htup;
+ ExpandedArrayHeader *eah;
+ HeapTupleHeader td;
+ HeapTupleData tmptup;
+ HeapTuple tup;
+
+ htup = SearchSysCache1(STATEXTDATASTXOID, ObjectIdGetDatum(stxoid));
+ if (!HeapTupleIsValid(htup))
+ elog(ERROR, "cache lookup failed for statistics object %u", stxoid);
+
+ value = SysCacheGetAttr(STATEXTDATASTXOID, htup,
+ Anum_pg_statistic_ext_data_stxdexpr, &isnull);
+ if (isnull)
+ elog(ERROR,
+ "requested statistics kind \"%c\" is not yet built for statistics object %u",
+ STATS_EXT_DEPENDENCIES, stxoid);
+
+ eah = DatumGetExpandedArray(value);
+
+ deconstruct_expanded_array(eah);
+
+ td = DatumGetHeapTupleHeader(eah->dvalues[idx]);
+
+ /* Build a temporary HeapTuple control structure */
+ tmptup.t_len = HeapTupleHeaderGetDatumLength(td);
+ tmptup.t_data = td;
+
+ tup = heap_copytuple(&tmptup);
+
+ ReleaseSysCache(htup);
+
+ return tup;
+}
+
+/*
+ * Evaluate the expressions, so that we can use the results to build
+ * all the requested statistics types. This matters especially for
+ * expensive expressions, of course.
+ */
+static ExprInfo *
+evaluate_expressions(Relation rel, List *exprs, int numrows, HeapTuple *rows)
+{
+ /* evaluated expressions */
+ ExprInfo *result;
+ char *ptr;
+ Size len;
+
+ int i;
+ int idx;
+ TupleTableSlot *slot;
+ EState *estate;
+ ExprContext *econtext;
+ List *exprstates = NIL;
+ int nexprs = list_length(exprs);
+ ListCell *lc;
+
+ /* allocate everything as a single chunk, so we can free it easily */
+ len = MAXALIGN(sizeof(ExprInfo));
+ len += MAXALIGN(sizeof(Oid) * nexprs); /* types */
+ len += MAXALIGN(sizeof(Oid) * nexprs); /* collations */
+
+ /* values */
+ len += MAXALIGN(sizeof(Datum *) * nexprs);
+ len += nexprs * MAXALIGN(sizeof(Datum) * numrows);
+
+ /* nulls */
+ len += MAXALIGN(sizeof(bool *) * nexprs);
+ len += nexprs * MAXALIGN(sizeof(bool) * numrows);
+
+ ptr = palloc(len);
+
+ /* set the pointers */
+ result = (ExprInfo *) ptr;
+ ptr += sizeof(ExprInfo);
+
+ /* types */
+ result->types = (Oid *) ptr;
+ ptr += MAXALIGN(sizeof(Oid) * nexprs);
+
+ /* collations */
+ result->collations = (Oid *) ptr;
+ ptr += MAXALIGN(sizeof(Oid) * nexprs);
+
+ /* values */
+ result->values = (Datum **) ptr;
+ ptr += MAXALIGN(sizeof(Datum *) * nexprs);
+
+ /* nulls */
+ result->nulls = (bool **) ptr;
+ ptr += MAXALIGN(sizeof(bool *) * nexprs);
+
+ for (i = 0; i < nexprs; i++)
+ {
+ result->values[i] = (Datum *) ptr;
+ ptr += MAXALIGN(sizeof(Datum) * numrows);
+
+ result->nulls[i] = (bool *) ptr;
+ ptr += MAXALIGN(sizeof(bool) * numrows);
+ }
+
+ Assert((ptr - (char *) result) == len);
+
+ result->nexprs = list_length(exprs);
+
+ idx = 0;
+ foreach (lc, exprs)
+ {
+ Node *expr = (Node *) lfirst(lc);
+
+ result->types[idx] = exprType(expr);
+ result->collations[idx] = exprCollation(expr);
+
+ idx++;
+ }
+
+ /*
+ * Need an EState for evaluation of index expressions and
+ * partial-index predicates. Create it in the per-index context to be
+ * sure it gets cleaned up at the bottom of the loop.
+ */
+ estate = CreateExecutorState();
+ econtext = GetPerTupleExprContext(estate);
+
+ /* Need a slot to hold the current heap tuple, too */
+ slot = MakeSingleTupleTableSlot(RelationGetDescr(rel),
+ &TTSOpsHeapTuple);
+
+ /* Arrange for econtext's scan tuple to be the tuple under test */
+ econtext->ecxt_scantuple = slot;
+
+ /* Set up expression evaluation state */
+ exprstates = ExecPrepareExprList(exprs, estate);
+
+ for (i = 0; i < numrows; i++)
+ {
+ /*
+ * Reset the per-tuple context each time, to reclaim any cruft
+ * left behind by evaluating the predicate or index expressions.
+ */
+ ResetExprContext(econtext);
+
+ /* Set up for predicate or expression evaluation */
+ ExecStoreHeapTuple(rows[i], slot, false);
+
+ idx = 0;
+ foreach (lc, exprstates)
+ {
+ Datum datum;
+ bool isnull;
+ ExprState *exprstate = (ExprState *) lfirst(lc);
+
+ /*
+ * FIXME this probably leaks memory. Maybe we should use
+ * ExecEvalExprSwitchContext but then we need to copy the
+ * result somewhere else.
+ */
+ datum = ExecEvalExpr(exprstate,
+ GetPerTupleExprContext(estate),
+ &isnull);
+ if (isnull)
+ {
+ result->values[idx][i] = (Datum) 0;
+ result->nulls[idx][i] = true;
+ }
+ else
+ {
+ result->values[idx][i] = (Datum) datum;
+ result->nulls[idx][i] = false;
+ }
+
+ idx++;
+ }
+ }
+
+ ExecDropSingleTupleTableSlot(slot);
+ FreeExecutorState(estate);
+
+ return result;
+}
+
+/*
+ * add_expressions_to_attributes
+ * add expressions as attributes with high attnums
+ *
+ * Treat the expressions as attributes with attnums above the regular
+ * attnum range. This will allow us to handle everything in the same
+ * way, and identify expressions in the dependencies.
+ *
+ * XXX This always creates a copy of the bitmap. We might optimize this
+ * by only creating the copy with (nexprs > 0) but then we'd have to track
+ * this in order to free it (if we want to). Does not seem worth it.
+ */
+Bitmapset *
+add_expressions_to_attributes(Bitmapset *attrs, int nexprs)
+{
+ int i;
+
+ /*
+ * Copy the bitmapset and add fake attnums representing expressions,
+ * starting above MaxHeapAttributeNumber.
+ */
+ attrs = bms_copy(attrs);
+
+ /* start with (MaxHeapAttributeNumber + 1) */
+ for (i = 0; i < nexprs; i++)
+ {
+ Assert(EXPRESSION_ATTNUM(i) > MaxHeapAttributeNumber);
+
+ attrs = bms_add_member(attrs, EXPRESSION_ATTNUM(i));
+ }
+
+ return attrs;
+}
diff --git a/src/backend/statistics/mcv.c b/src/backend/statistics/mcv.c
index abbc1f1ba8..0c27ee395e 100644
--- a/src/backend/statistics/mcv.c
+++ b/src/backend/statistics/mcv.c
@@ -74,7 +74,8 @@
((ndims) * sizeof(DimensionInfo)) + \
((nitems) * ITEM_SIZE(ndims)))
-static MultiSortSupport build_mss(VacAttrStats **stats, int numattrs);
+static MultiSortSupport build_mss(VacAttrStats **stats, int numattrs,
+ ExprInfo *exprs);
static SortItem *build_distinct_groups(int numrows, SortItem *items,
MultiSortSupport mss, int *ndistinct);
@@ -181,8 +182,9 @@ get_mincount_for_mcv_list(int samplerows, double totalrows)
*
*/
MCVList *
-statext_mcv_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
- VacAttrStats **stats, double totalrows, int stattarget)
+statext_mcv_build(int numrows, HeapTuple *rows, ExprInfo *exprs,
+ Bitmapset *attrs, VacAttrStats **stats,
+ double totalrows, int stattarget)
{
int i,
numattrs,
@@ -195,14 +197,23 @@ statext_mcv_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
MCVList *mcvlist = NULL;
MultiSortSupport mss;
- attnums = build_attnums_array(attrs, &numattrs);
-
/* comparator for all the columns */
- mss = build_mss(stats, numattrs);
+ mss = build_mss(stats, bms_num_members(attrs), exprs);
+
+ /*
+ * treat expressions as special attributes with high attnums
+ *
+ * XXX We do this after build_mss, because that expects the bitmapset
+ * to only contain simple attributes (with a matching VacAttrStats)
+ */
+ attrs = add_expressions_to_attributes(attrs, exprs->nexprs);
+
+ /* now build the array, with the special expression attnums */
+ attnums = build_attnums_array(attrs, &numattrs);
/* sort the rows */
- items = build_sorted_items(numrows, &nitems, rows, stats[0]->tupDesc,
- mss, numattrs, attnums);
+ items = build_sorted_items(numrows, &nitems, rows, exprs,
+ stats[0]->tupDesc, mss, numattrs, attnums);
if (!items)
return NULL;
@@ -338,6 +349,7 @@ statext_mcv_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
pfree(items);
pfree(groups);
+ pfree(attrs);
return mcvlist;
}
@@ -347,12 +359,12 @@ statext_mcv_build(int numrows, HeapTuple *rows, Bitmapset *attrs,
* build MultiSortSupport for the attributes passed in attrs
*/
static MultiSortSupport
-build_mss(VacAttrStats **stats, int numattrs)
+build_mss(VacAttrStats **stats, int numattrs, ExprInfo *exprs)
{
int i;
/* Sort by multiple columns (using array of SortSupport) */
- MultiSortSupport mss = multi_sort_init(numattrs);
+ MultiSortSupport mss = multi_sort_init(numattrs + exprs->nexprs);
/* prepare the sort functions for all the attributes */
for (i = 0; i < numattrs; i++)
@@ -368,6 +380,20 @@ build_mss(VacAttrStats **stats, int numattrs)
multi_sort_add_dimension(mss, i, type->lt_opr, colstat->attrcollid);
}
+ /* prepare the sort functions for all the expressions */
+ for (i = 0; i < exprs->nexprs; i++)
+ {
+ TypeCacheEntry *type;
+
+ type = lookup_type_cache(exprs->types[i], TYPECACHE_LT_OPR);
+ if (type->lt_opr == InvalidOid) /* shouldn't happen */
+ elog(ERROR, "cache lookup failed for ordering operator for type %u",
+ exprs->types[i]);
+
+ multi_sort_add_dimension(mss, numattrs + i, type->lt_opr,
+ exprs->collations[i]);
+ }
+
return mss;
}
@@ -570,7 +596,7 @@ statext_mcv_load(Oid mvoid)
if (isnull)
elog(ERROR,
- "requested statistic kind \"%c\" is not yet built for statistics object %u",
+ "requested statistics kind \"%c\" is not yet built for statistics object %u",
STATS_EXT_DEPENDENCIES, mvoid);
result = statext_mcv_deserialize(DatumGetByteaP(mcvlist));
@@ -1541,10 +1567,14 @@ pg_mcv_list_send(PG_FUNCTION_ARGS)
* the size to ~1/8. It would also allow us to combine bitmaps simply using
* & and |, which should be faster than min/max. The bitmaps are fairly
* small, though (thanks to the cap on the MCV list size).
+ *
+ * XXX There's a lot of code duplication between branches for simple columns
+ * and complex expressions. We should refactor it somehow.
*/
static bool *
mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
- Bitmapset *keys, MCVList *mcvlist, bool is_or)
+ Bitmapset *keys, List *exprs,
+ MCVList *mcvlist, bool is_or)
{
int i;
ListCell *l;
@@ -1584,8 +1614,10 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
/* valid only after examine_clause_args returns true */
Var *var;
+ Node *clause_expr;
Const *cst;
bool varonleft;
+ bool expronleft;
fmgr_info(get_opcode(expr->opno), &opproc);
@@ -1654,6 +1686,89 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
matches[i] = RESULT_MERGE(matches[i], is_or, match);
}
}
+ /* extract the expr and const from the expression */
+ else if (examine_clause_args2(expr->args, &clause_expr, &cst, &expronleft))
+ {
+ ListCell *lc;
+ int idx;
+ Oid collid = exprCollation(clause_expr);
+
+ /* match the attribute to a dimension of the statistic */
+ idx = bms_num_members(keys);
+
+ foreach(lc, exprs)
+ {
+ Node *stat_expr = (Node *) lfirst(lc);
+
+ if (equal(clause_expr, stat_expr))
+ break;
+
+ idx++;
+ }
+
+ /* index should be valid */
+ Assert((idx >= 0) &&
+ (idx < bms_num_members(keys) + list_length(exprs)));
+
+ /*
+ * Walk through the MCV items and evaluate the current clause.
+ * We can skip items that were already ruled out, and
+ * terminate if there are no remaining MCV items that might
+ * possibly match.
+ */
+ for (i = 0; i < mcvlist->nitems; i++)
+ {
+ bool match = true;
+ MCVItem *item = &mcvlist->items[i];
+
+ /*
+ * When the MCV item or the Const value is NULL we can
+ * treat this as a mismatch. We must not call the operator
+ * because of strictness.
+ */
+ if (item->isnull[idx] || cst->constisnull)
+ {
+ matches[i] = RESULT_MERGE(matches[i], is_or, false);
+ continue;
+ }
+
+ /*
+ * Skip MCV items that can't change result in the bitmap.
+ * Once the value gets false for AND-lists, or true for
+ * OR-lists, we don't need to look at more clauses.
+ */
+ if (RESULT_IS_FINAL(matches[i], is_or))
+ continue;
+
+ /*
+ * First check whether the constant is below the lower
+ * boundary (in that case we can skip the bucket, because
+ * there's no overlap).
+ *
+ * We don't store collations used to build the statistics,
+ * but we can use the collation for the attribute itself,
+ * as stored in varcollid. We do reset the statistics
+ * after a type change (including collation change), so
+ * this is OK. We may need to relax this after allowing
+ * extended statistics on expressions.
+ */
+ if (expronleft)
+ match = DatumGetBool(FunctionCall2Coll(&opproc,
+ collid,
+ item->values[idx],
+ cst->constvalue));
+ else
+ match = DatumGetBool(FunctionCall2Coll(&opproc,
+ collid,
+ cst->constvalue,
+ item->values[idx]));
+
+ /* update the match bitmap with the result */
+ matches[i] = RESULT_MERGE(matches[i], is_or, match);
+ }
+ }
+ else
+ elog(ERROR, "incompatible clause");
}
else if (IsA(clause, ScalarArrayOpExpr))
{
@@ -1662,8 +1777,10 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
/* valid only after examine_clause_args returns true */
Var *var;
+ Node *clause_expr;
Const *cst;
bool varonleft;
+ bool expronleft;
fmgr_info(get_opcode(expr->opno), &opproc);
@@ -1761,14 +1878,155 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
matches[i] = RESULT_MERGE(matches[i], is_or, match);
}
}
+ /* extract the expr and const from the expression */
+ else if (examine_clause_args2(expr->args, &clause_expr, &cst, &expronleft))
+ {
+ ListCell *lc;
+ int idx;
+
+ ArrayType *arrayval;
+ int16 elmlen;
+ bool elmbyval;
+ char elmalign;
+ int num_elems;
+ Datum *elem_values;
+ bool *elem_nulls;
+ Oid collid = exprCollation(clause_expr);
+
+ /* ScalarArrayOpExpr has the Var always on the left */
+ Assert(expronleft);
+
+ if (!cst->constisnull)
+ {
+ arrayval = DatumGetArrayTypeP(cst->constvalue);
+ get_typlenbyvalalign(ARR_ELEMTYPE(arrayval),
+ &elmlen, &elmbyval, &elmalign);
+ deconstruct_array(arrayval,
+ ARR_ELEMTYPE(arrayval),
+ elmlen, elmbyval, elmalign,
+ &elem_values, &elem_nulls, &num_elems);
+ }
+
+ /* match the attribute to a dimension of the statistic */
+ idx = bms_num_members(keys);
+
+ foreach(lc, exprs)
+ {
+ Node *stat_expr = (Node *) lfirst(lc);
+
+ if (equal(clause_expr, stat_expr))
+ break;
+
+ idx++;
+ }
+
+ /* index should be valid */
+ Assert((idx >= 0) &&
+ (idx < bms_num_members(keys) + list_length(exprs)));
+
+ /*
+ * Walk through the MCV items and evaluate the current clause.
+ * We can skip items that were already ruled out, and
+ * terminate if there are no remaining MCV items that might
+ * possibly match.
+ */
+ for (i = 0; i < mcvlist->nitems; i++)
+ {
+ int j;
+ bool match = (expr->useOr ? false : true);
+ MCVItem *item = &mcvlist->items[i];
+
+ /*
+ * When the MCV item or the Const value is NULL we can
+ * treat this as a mismatch. We must not call the operator
+ * because of strictness.
+ */
+ if (item->isnull[idx] || cst->constisnull)
+ {
+ matches[i] = RESULT_MERGE(matches[i], is_or, false);
+ continue;
+ }
+
+ /*
+ * Skip MCV items that can't change result in the bitmap.
+ * Once the value gets false for AND-lists, or true for
+ * OR-lists, we don't need to look at more clauses.
+ */
+ if (RESULT_IS_FINAL(matches[i], is_or))
+ continue;
+
+ for (j = 0; j < num_elems; j++)
+ {
+ Datum elem_value = elem_values[j];
+ bool elem_isnull = elem_nulls[j];
+ bool elem_match;
+
+ /* NULL values always evaluate as not matching. */
+ if (elem_isnull)
+ {
+ match = RESULT_MERGE(match, expr->useOr, false);
+ continue;
+ }
+
+ /*
+ * Stop evaluating the array elements once we reach
+ * match value that can't change - ALL() is the same
+ * as AND-list, ANY() is the same as OR-list.
+ */
+ if (RESULT_IS_FINAL(match, expr->useOr))
+ break;
+
+ elem_match = DatumGetBool(FunctionCall2Coll(&opproc,
+ collid,
+ item->values[idx],
+ elem_value));
+
+ match = RESULT_MERGE(match, expr->useOr, elem_match);
+ }
+
+ /* update the match bitmap with the result */
+ matches[i] = RESULT_MERGE(matches[i], is_or, match);
+ }
+ }
+ else
+ elog(ERROR, "incompatible clause");
}
else if (IsA(clause, NullTest))
{
NullTest *expr = (NullTest *) clause;
- Var *var = (Var *) (expr->arg);
+ Node *clause_expr = (Node *) (expr->arg);
/* match the attribute to a dimension of the statistic */
- int idx = bms_member_index(keys, var->varattno);
+ int idx = -1;
+
+ if (IsA(clause_expr, Var))
+ {
+ /* simple Var, so just lookup using varattno */
+ Var *var = (Var *) clause_expr;
+
+ idx = bms_member_index(keys, var->varattno);
+ }
+ else
+ {
+ ListCell *lc;
+
+ /* expressions are after the simple columns */
+ idx = bms_num_members(keys);
+
+ /* expression - lookup in stats expressions */
+ foreach(lc, exprs)
+ {
+ Node *stat_expr = (Node *) lfirst(lc);
+
+ if (equal(clause_expr, stat_expr))
+ break;
+
+ idx++;
+ }
+ }
+
+ /* index should be valid */
+ Assert((idx >= 0) && (idx < bms_num_members(keys) + list_length(exprs)));
/*
* Walk through the MCV items and evaluate the current clause. We
@@ -1811,7 +2069,7 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
Assert(list_length(bool_clauses) >= 2);
/* build the match bitmap for the OR-clauses */
- bool_matches = mcv_get_match_bitmap(root, bool_clauses, keys,
+ bool_matches = mcv_get_match_bitmap(root, bool_clauses, keys, exprs,
mcvlist, is_orclause(clause));
/*
@@ -1839,7 +2097,7 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
Assert(list_length(not_args) == 1);
/* build the match bitmap for the NOT-clause */
- not_matches = mcv_get_match_bitmap(root, not_args, keys,
+ not_matches = mcv_get_match_bitmap(root, not_args, keys, exprs,
mcvlist, false);
/*
@@ -1982,7 +2240,8 @@ mcv_clauselist_selectivity(PlannerInfo *root, StatisticExtInfo *stat,
mcv = statext_mcv_load(stat->statOid);
/* build a match bitmap for the clauses */
- matches = mcv_get_match_bitmap(root, clauses, stat->keys, mcv, false);
+ matches = mcv_get_match_bitmap(root, clauses, stat->keys, stat->exprs,
+ mcv, false);
/* sum frequencies for all the matching MCV items */
*basesel = 0.0;
@@ -2056,7 +2315,7 @@ mcv_clause_selectivity_or(PlannerInfo *root, StatisticExtInfo *stat,
/* build the match bitmap for the new clause */
new_matches = mcv_get_match_bitmap(root, list_make1(clause), stat->keys,
- mcv, false);
+ stat->exprs, mcv, false);
/*
* Sum the frequencies for all the MCV items matching this clause and also
diff --git a/src/backend/statistics/mvdistinct.c b/src/backend/statistics/mvdistinct.c
index 9ef21debb6..55d3fa0e1f 100644
--- a/src/backend/statistics/mvdistinct.c
+++ b/src/backend/statistics/mvdistinct.c
@@ -37,7 +37,8 @@
#include "utils/typcache.h"
static double ndistinct_for_combination(double totalrows, int numrows,
- HeapTuple *rows, VacAttrStats **stats,
+ HeapTuple *rows, ExprInfo *exprs,
+ int nattrs, VacAttrStats **stats,
int k, int *combination);
static double estimate_ndistinct(double totalrows, int numrows, int d, int f1);
static int n_choose_k(int n, int k);
@@ -81,16 +82,21 @@ static void generate_combinations(CombinationGenerator *state);
*
* This computes the ndistinct estimate using the same estimator used
* in analyze.c and then computes the coefficient.
+ *
+ * To handle expressions easily, we treat them as special attributes with
+ * attnums above MaxHeapAttributeNumber, and we assume the expressions are
+ * placed after all simple attributes.
*/
MVNDistinct *
statext_ndistinct_build(double totalrows, int numrows, HeapTuple *rows,
- Bitmapset *attrs, VacAttrStats **stats)
+ ExprInfo *exprs, Bitmapset *attrs,
+ VacAttrStats **stats)
{
MVNDistinct *result;
int k;
int itemcnt;
int numattrs = bms_num_members(attrs);
- int numcombs = num_combinations(numattrs);
+ int numcombs = num_combinations(numattrs + exprs->nexprs);
result = palloc(offsetof(MVNDistinct, items) +
numcombs * sizeof(MVNDistinctItem));
@@ -98,14 +104,20 @@ statext_ndistinct_build(double totalrows, int numrows, HeapTuple *rows,
result->type = STATS_NDISTINCT_TYPE_BASIC;
result->nitems = numcombs;
+ /* treat expressions as special attributes with high attnums */
+ attrs = add_expressions_to_attributes(attrs, exprs->nexprs);
+
+ /* make sure there were no clashes */
+ Assert(bms_num_members(attrs) == numattrs + exprs->nexprs);
+
itemcnt = 0;
- for (k = 2; k <= numattrs; k++)
+ for (k = 2; k <= bms_num_members(attrs); k++)
{
int *combination;
CombinationGenerator *generator;
/* generate combinations of K out of N elements */
- generator = generator_init(numattrs, k);
+ generator = generator_init(bms_num_members(attrs), k);
while ((combination = generator_next(generator)))
{
@@ -114,10 +126,32 @@ statext_ndistinct_build(double totalrows, int numrows, HeapTuple *rows,
item->attrs = NULL;
for (j = 0; j < k; j++)
- item->attrs = bms_add_member(item->attrs,
- stats[combination[j]]->attr->attnum);
+ {
+ AttrNumber attnum = InvalidAttrNumber;
+
+ /*
+ * The simple attributes are before expressions, so have
+ * indexes below numattrs.
+ * */
+ if (combination[j] < numattrs)
+ attnum = stats[combination[j]]->attr->attnum;
+ else
+ {
+ /* make sure the expression index is valid */
+ Assert((combination[j] - numattrs) >= 0);
+ Assert((combination[j] - numattrs) < exprs->nexprs);
+
+ attnum = EXPRESSION_ATTNUM(combination[j] - numattrs);
+ }
+
+ Assert(attnum != InvalidAttrNumber);
+
+ item->attrs = bms_add_member(item->attrs, attnum);
+ }
+
item->ndistinct =
ndistinct_for_combination(totalrows, numrows, rows,
+ exprs, numattrs,
stats, k, combination);
itemcnt++;
@@ -153,7 +187,7 @@ statext_ndistinct_load(Oid mvoid)
Anum_pg_statistic_ext_data_stxdndistinct, &isnull);
if (isnull)
elog(ERROR,
- "requested statistic kind \"%c\" is not yet built for statistics object %u",
+ "requested statistics kind \"%c\" is not yet built for statistics object %u",
STATS_EXT_NDISTINCT, mvoid);
result = statext_ndistinct_deserialize(DatumGetByteaPP(ndist));
@@ -428,6 +462,7 @@ pg_ndistinct_send(PG_FUNCTION_ARGS)
*/
static double
ndistinct_for_combination(double totalrows, int numrows, HeapTuple *rows,
+ ExprInfo *exprs, int nattrs,
VacAttrStats **stats, int k, int *combination)
{
int i,
@@ -467,25 +502,57 @@ ndistinct_for_combination(double totalrows, int numrows, HeapTuple *rows,
*/
for (i = 0; i < k; i++)
{
- VacAttrStats *colstat = stats[combination[i]];
+ Oid typid;
TypeCacheEntry *type;
+ AttrNumber attnum = InvalidAttrNumber;
+ TupleDesc tdesc = NULL;
+ Oid collid = InvalidOid;
+
+ if (combination[i] < nattrs)
+ {
+ VacAttrStats *colstat = stats[combination[i]];
+ typid = colstat->attrtypid;
+ attnum = colstat->attr->attnum;
+ collid = colstat->attrcollid;
+ tdesc = colstat->tupDesc;
+ }
+ else
+ {
+ typid = exprs->types[combination[i] - nattrs];
+ collid = exprs->collations[combination[i] - nattrs];
+ }
- type = lookup_type_cache(colstat->attrtypid, TYPECACHE_LT_OPR);
+ type = lookup_type_cache(typid, TYPECACHE_LT_OPR);
if (type->lt_opr == InvalidOid) /* shouldn't happen */
elog(ERROR, "cache lookup failed for ordering operator for type %u",
- colstat->attrtypid);
+ typid);
/* prepare the sort function for this dimension */
- multi_sort_add_dimension(mss, i, type->lt_opr, colstat->attrcollid);
+ multi_sort_add_dimension(mss, i, type->lt_opr, collid);
/* accumulate all the data for this dimension into the arrays */
for (j = 0; j < numrows; j++)
{
- items[j].values[i] =
- heap_getattr(rows[j],
- colstat->attr->attnum,
- colstat->tupDesc,
- &items[j].isnull[i]);
+ /*
+ * The first nattrs indexes identify simple attributes, higher
+ * indexes are expressions.
+ */
+ if (combination[i] < nattrs)
+ items[j].values[i] =
+ heap_getattr(rows[j],
+ attnum,
+ tdesc,
+ &items[j].isnull[i]);
+ else
+ {
+ int idx = (combination[i] - nattrs);
+
+ /* make sure the expression index is valid */
+ Assert((idx >= 0) && (idx < exprs->nexprs));
+
+ items[j].values[i] = exprs->values[idx][j];
+ items[j].isnull[i] = exprs->nulls[idx][j];
+ }
}
}
diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index 53a511f1da..053e4d1d91 100644
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -1834,7 +1834,28 @@ ProcessUtilitySlow(ParseState *pstate,
break;
case T_CreateStatsStmt:
- address = CreateStatistics((CreateStatsStmt *) parsetree);
+ {
+ Oid relid;
+ CreateStatsStmt *stmt = (CreateStatsStmt *) parsetree;
+ RangeVar *rel = (RangeVar *) linitial(stmt->relations);
+
+ /*
+ * CREATE STATISTICS will influence future execution plans
+ * but does not interfere with currently executing plans.
+ * So it should be enough to take ShareUpdateExclusiveLock
+ * on relation, conflicting with ANALYZE and other DDL that
+ * sets statistical information, but not with normal queries.
+ *
+ * XXX RangeVarCallbackOwnsRelation not needed needed here,
+ * to keep the same behavior as before.
+ */
+ relid = RangeVarGetRelid(rel, ShareUpdateExclusiveLock, false);
+
+ /* Run parse analysis ... */
+ stmt = transformStatsStmt(relid, stmt, queryString);
+
+ address = CreateStatistics(stmt);
+ }
break;
case T_AlterStatsStmt:
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index db803b4388..ea36d6c6ff 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -336,7 +336,8 @@ static char *pg_get_indexdef_worker(Oid indexrelid, int colno,
bool attrsOnly, bool keysOnly,
bool showTblSpc, bool inherits,
int prettyFlags, bool missing_ok);
-static char *pg_get_statisticsobj_worker(Oid statextid, bool missing_ok);
+static char *pg_get_statisticsobj_worker(Oid statextid, bool columns_only,
+ bool missing_ok);
static char *pg_get_partkeydef_worker(Oid relid, int prettyFlags,
bool attrsOnly, bool missing_ok);
static char *pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
@@ -1507,7 +1508,26 @@ pg_get_statisticsobjdef(PG_FUNCTION_ARGS)
Oid statextid = PG_GETARG_OID(0);
char *res;
- res = pg_get_statisticsobj_worker(statextid, true);
+ res = pg_get_statisticsobj_worker(statextid, false, true);
+
+ if (res == NULL)
+ PG_RETURN_NULL();
+
+ PG_RETURN_TEXT_P(string_to_text(res));
+}
+
+
+/*
+ * pg_get_statisticsobjdef_columns
+ * Get columns and expressions for an extended statistics object
+ */
+Datum
+pg_get_statisticsobjdef_columns(PG_FUNCTION_ARGS)
+{
+ Oid statextid = PG_GETARG_OID(0);
+ char *res;
+
+ res = pg_get_statisticsobj_worker(statextid, true, true);
if (res == NULL)
PG_RETURN_NULL();
@@ -1519,7 +1539,7 @@ pg_get_statisticsobjdef(PG_FUNCTION_ARGS)
* Internal workhorse to decompile an extended statistics object.
*/
static char *
-pg_get_statisticsobj_worker(Oid statextid, bool missing_ok)
+pg_get_statisticsobj_worker(Oid statextid, bool columns_only, bool missing_ok)
{
Form_pg_statistic_ext statextrec;
HeapTuple statexttup;
@@ -1534,6 +1554,11 @@ pg_get_statisticsobj_worker(Oid statextid, bool missing_ok)
bool dependencies_enabled;
bool mcv_enabled;
int i;
+ List *context;
+ ListCell *lc;
+ List *exprs = NIL;
+ bool has_exprs;
+ int ncolumns;
statexttup = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(statextid));
@@ -1544,75 +1569,112 @@ pg_get_statisticsobj_worker(Oid statextid, bool missing_ok)
elog(ERROR, "cache lookup failed for statistics object %u", statextid);
}
- statextrec = (Form_pg_statistic_ext) GETSTRUCT(statexttup);
-
- initStringInfo(&buf);
+ /* has the statistics expressions? */
+ has_exprs = !heap_attisnull(statexttup, Anum_pg_statistic_ext_stxexprs, NULL);
- nsp = get_namespace_name(statextrec->stxnamespace);
- appendStringInfo(&buf, "CREATE STATISTICS %s",
- quote_qualified_identifier(nsp,
- NameStr(statextrec->stxname)));
+ statextrec = (Form_pg_statistic_ext) GETSTRUCT(statexttup);
/*
- * Decode the stxkind column so that we know which stats types to print.
+ * Get the statistics expressions, if any. (NOTE: we do not use the
+ * relcache versions of the expressions and predicate, because we want
+ * to display non-const-folded expressions.)
*/
- datum = SysCacheGetAttr(STATEXTOID, statexttup,
- Anum_pg_statistic_ext_stxkind, &isnull);
- Assert(!isnull);
- arr = DatumGetArrayTypeP(datum);
- if (ARR_NDIM(arr) != 1 ||
- ARR_HASNULL(arr) ||
- ARR_ELEMTYPE(arr) != CHAROID)
- elog(ERROR, "stxkind is not a 1-D char array");
- enabled = (char *) ARR_DATA_PTR(arr);
-
- ndistinct_enabled = false;
- dependencies_enabled = false;
- mcv_enabled = false;
-
- for (i = 0; i < ARR_DIMS(arr)[0]; i++)
+ if (has_exprs)
{
- if (enabled[i] == STATS_EXT_NDISTINCT)
- ndistinct_enabled = true;
- if (enabled[i] == STATS_EXT_DEPENDENCIES)
- dependencies_enabled = true;
- if (enabled[i] == STATS_EXT_MCV)
- mcv_enabled = true;
+ Datum exprsDatum;
+ bool isnull;
+ char *exprsString;
+
+ exprsDatum = SysCacheGetAttr(STATEXTOID, statexttup,
+ Anum_pg_statistic_ext_stxexprs, &isnull);
+ Assert(!isnull);
+ exprsString = TextDatumGetCString(exprsDatum);
+ exprs = (List *) stringToNode(exprsString);
+ pfree(exprsString);
}
+ else
+ exprs = NIL;
- /*
- * If any option is disabled, then we'll need to append the types clause
- * to show which options are enabled. We omit the types clause on purpose
- * when all options are enabled, so a pg_dump/pg_restore will create all
- * statistics types on a newer postgres version, if the statistics had all
- * options enabled on the original version.
- */
- if (!ndistinct_enabled || !dependencies_enabled || !mcv_enabled)
+ /* count the number of columns (attributes and expressions) */
+ ncolumns = statextrec->stxkeys.dim1 + list_length(exprs);
+
+ initStringInfo(&buf);
+
+ if (!columns_only)
{
- bool gotone = false;
+ nsp = get_namespace_name(statextrec->stxnamespace);
+ appendStringInfo(&buf, "CREATE STATISTICS %s",
+ quote_qualified_identifier(nsp,
+ NameStr(statextrec->stxname)));
- appendStringInfoString(&buf, " (");
+ /*
+ * Decode the stxkind column so that we know which stats types to print.
+ */
+ datum = SysCacheGetAttr(STATEXTOID, statexttup,
+ Anum_pg_statistic_ext_stxkind, &isnull);
+ Assert(!isnull);
+ arr = DatumGetArrayTypeP(datum);
+ if (ARR_NDIM(arr) != 1 ||
+ ARR_HASNULL(arr) ||
+ ARR_ELEMTYPE(arr) != CHAROID)
+ elog(ERROR, "stxkind is not a 1-D char array");
+ enabled = (char *) ARR_DATA_PTR(arr);
+
+ ndistinct_enabled = false;
+ dependencies_enabled = false;
+ mcv_enabled = false;
- if (ndistinct_enabled)
+ for (i = 0; i < ARR_DIMS(arr)[0]; i++)
{
- appendStringInfoString(&buf, "ndistinct");
- gotone = true;
+ if (enabled[i] == STATS_EXT_NDISTINCT)
+ ndistinct_enabled = true;
+ if (enabled[i] == STATS_EXT_DEPENDENCIES)
+ dependencies_enabled = true;
+ if (enabled[i] == STATS_EXT_MCV)
+ mcv_enabled = true;
+
+ /* ignore STATS_EXT_EXPRESSIONS (it's built automatically) */
}
- if (dependencies_enabled)
+ /*
+ * If any option is disabled, then we'll need to append the types clause
+ * to show which options are enabled. We omit the types clause on purpose
+ * when all options are enabled, so a pg_dump/pg_restore will create all
+ * statistics types on a newer postgres version, if the statistics had all
+ * options enabled on the original version.
+ *
+ * But if the statistics is defined on just a single column, it has to be
+ * an expression statistics. In that case we don't need to specify kinds.
+ */
+ if ((!ndistinct_enabled || !dependencies_enabled || !mcv_enabled) &&
+ (ncolumns > 1))
{
- appendStringInfo(&buf, "%sdependencies", gotone ? ", " : "");
- gotone = true;
- }
+ bool gotone = false;
- if (mcv_enabled)
- appendStringInfo(&buf, "%smcv", gotone ? ", " : "");
+ appendStringInfoString(&buf, " (");
- appendStringInfoChar(&buf, ')');
- }
+ if (ndistinct_enabled)
+ {
+ appendStringInfoString(&buf, "ndistinct");
+ gotone = true;
+ }
+
+ if (dependencies_enabled)
+ {
+ appendStringInfo(&buf, "%sdependencies", gotone ? ", " : "");
+ gotone = true;
+ }
- appendStringInfoString(&buf, " ON ");
+ if (mcv_enabled)
+ appendStringInfo(&buf, "%smcv", gotone ? ", " : "");
+ appendStringInfoChar(&buf, ')');
+ }
+
+ appendStringInfoString(&buf, " ON ");
+ }
+
+ /* decode simple column references */
for (colno = 0; colno < statextrec->stxkeys.dim1; colno++)
{
AttrNumber attnum = statextrec->stxkeys.values[colno];
@@ -1626,14 +1688,109 @@ pg_get_statisticsobj_worker(Oid statextid, bool missing_ok)
appendStringInfoString(&buf, quote_identifier(attname));
}
- appendStringInfo(&buf, " FROM %s",
- generate_relation_name(statextrec->stxrelid, NIL));
+ context = deparse_context_for(get_relation_name(statextrec->stxrelid),
+ statextrec->stxrelid);
+
+ foreach (lc, exprs)
+ {
+ Node *expr = (Node *) lfirst(lc);
+ char *str;
+ int prettyFlags = PRETTYFLAG_INDENT;
+
+ str = deparse_expression_pretty(expr, context, false, false,
+ prettyFlags, 0);
+
+ if (colno > 0)
+ appendStringInfoString(&buf, ", ");
+
+ /* Need parens if it's not a bare function call */
+ if (looks_like_function(expr))
+ appendStringInfoString(&buf, str);
+ else
+ appendStringInfo(&buf, "(%s)", str);
+
+ colno++;
+ }
+
+ if (!columns_only)
+ appendStringInfo(&buf, " FROM %s",
+ generate_relation_name(statextrec->stxrelid, NIL));
ReleaseSysCache(statexttup);
return buf.data;
}
+/*
+ * Generate text array of expressions for statistics object.
+ */
+Datum
+pg_get_statisticsobjdef_expressions(PG_FUNCTION_ARGS)
+{
+ Oid statextid = PG_GETARG_OID(0);
+ Form_pg_statistic_ext statextrec;
+ HeapTuple statexttup;
+ Datum datum;
+ bool isnull;
+ List *context;
+ ListCell *lc;
+ List *exprs = NIL;
+ bool has_exprs;
+ char *tmp;
+ ArrayBuildState *astate = NULL;
+
+ statexttup = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(statextid));
+
+ if (!HeapTupleIsValid(statexttup))
+ elog(ERROR, "cache lookup failed for statistics object %u", statextid);
+
+ /* has the statistics expressions? */
+ has_exprs = !heap_attisnull(statexttup, Anum_pg_statistic_ext_stxexprs, NULL);
+
+ /* no expressions? we're done */
+ if (!has_exprs)
+ {
+ ReleaseSysCache(statexttup);
+ PG_RETURN_NULL();
+ }
+
+ statextrec = (Form_pg_statistic_ext) GETSTRUCT(statexttup);
+
+ /*
+ * Get the statistics expressions, and deparse them into text values.
+ */
+ datum = SysCacheGetAttr(STATEXTOID, statexttup,
+ Anum_pg_statistic_ext_stxexprs, &isnull);
+
+ Assert(!isnull);
+ tmp = TextDatumGetCString(datum);
+ exprs = (List *) stringToNode(tmp);
+ pfree(tmp);
+
+ context = deparse_context_for(get_relation_name(statextrec->stxrelid),
+ statextrec->stxrelid);
+
+ foreach (lc, exprs)
+ {
+ Node *expr = (Node *) lfirst(lc);
+ char *str;
+ int prettyFlags = PRETTYFLAG_INDENT;
+
+ str = deparse_expression_pretty(expr, context, false, false,
+ prettyFlags, 0);
+
+ astate = accumArrayResult(astate,
+ PointerGetDatum(cstring_to_text(str)),
+ false,
+ TEXTOID,
+ CurrentMemoryContext);
+ }
+
+ ReleaseSysCache(statexttup);
+
+ PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
+}
+
/*
* pg_get_partkeydef
*
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index d5e61664bc..b52ab25d78 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -3291,6 +3291,88 @@ add_unique_group_var(PlannerInfo *root, List *varinfos,
return varinfos;
}
+/*
+ * Helper routine for estimate_num_groups: add an item to a list of
+ * GroupExprInfos, but only if it's not known equal to any of the existing
+ * entries.
+ */
+typedef struct
+{
+ Node *expr; /* expression */
+ RelOptInfo *rel; /* relation it belongs to */
+ List *varinfos; /* info for variables in this expression */
+} GroupExprInfo;
+
+static List *
+add_unique_group_expr(PlannerInfo *root, List *exprinfos,
+ Node *expr, List *vars)
+{
+ GroupExprInfo *exprinfo;
+ ListCell *lc;
+ Bitmapset *varnos;
+ Index varno;
+
+ foreach(lc, exprinfos)
+ {
+ exprinfo = (GroupExprInfo *) lfirst(lc);
+
+ /* Drop exact duplicates */
+ if (equal(expr, exprinfo->expr))
+ return exprinfos;
+ }
+
+ exprinfo = (GroupExprInfo *) palloc(sizeof(GroupExprInfo));
+
+ varnos = pull_varnos(expr);
+
+ /*
+ * Expressions with vars from multiple relations should never get
+ * here, as we split them to vars.
+ */
+ Assert(bms_num_members(varnos) == 1);
+
+ varno = bms_singleton_member(varnos);
+
+ exprinfo->expr = expr;
+ exprinfo->varinfos = NIL;
+ exprinfo->rel = root->simple_rel_array[varno];
+
+ Assert(exprinfo->rel);
+
+ /* Track vars for this expression. */
+ foreach (lc, vars)
+ {
+ VariableStatData vardata;
+ Node *var = (Node *) lfirst(lc);
+
+ /* can we get no vardata for the variable? */
+ examine_variable(root, var, 0, &vardata);
+
+ exprinfo->varinfos
+ = add_unique_group_var(root, exprinfo->varinfos, var, &vardata);
+
+ ReleaseVariableStats(vardata);
+ }
+
+ /* without a list of variables, use the expression itself */
+ if (vars == NIL)
+ {
+ VariableStatData vardata;
+
+ /* can we get no vardata for the variable? */
+ examine_variable(root, expr, 0, &vardata);
+
+ exprinfo->varinfos
+ = add_unique_group_var(root, exprinfo->varinfos,
+ expr, &vardata);
+
+ ReleaseVariableStats(vardata);
+ }
+
+ return lappend(exprinfos, exprinfo);
+}
+
+
/*
* estimate_num_groups - Estimate number of groups in a grouped query
*
@@ -3360,7 +3442,7 @@ double
estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
List **pgset)
{
- List *varinfos = NIL;
+ List *exprinfos = NIL;
double srf_multiplier = 1.0;
double numdistinct;
ListCell *l;
@@ -3398,6 +3480,7 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
double this_srf_multiplier;
VariableStatData vardata;
List *varshere;
+ Relids varnos;
ListCell *l2;
/* is expression in this grouping set? */
@@ -3434,8 +3517,9 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
examine_variable(root, groupexpr, 0, &vardata);
if (HeapTupleIsValid(vardata.statsTuple) || vardata.isunique)
{
- varinfos = add_unique_group_var(root, varinfos,
- groupexpr, &vardata);
+ exprinfos = add_unique_group_expr(root, exprinfos,
+ groupexpr, NIL);
+
ReleaseVariableStats(vardata);
continue;
}
@@ -3465,6 +3549,19 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
continue;
}
+ /*
+ * Are all the variables from the same relation? If yes, search for
+ * an extended statistic matching this expression exactly.
+ */
+ varnos = pull_varnos((Node *) varshere);
+ if (bms_membership(varnos) == BMS_SINGLETON)
+ {
+ exprinfos = add_unique_group_expr(root, exprinfos,
+ groupexpr,
+ varshere);
+ continue;
+ }
+
/*
* Else add variables to varinfos list
*/
@@ -3472,9 +3569,8 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
{
Node *var = (Node *) lfirst(l2);
- examine_variable(root, var, 0, &vardata);
- varinfos = add_unique_group_var(root, varinfos, var, &vardata);
- ReleaseVariableStats(vardata);
+ exprinfos = add_unique_group_expr(root, exprinfos,
+ var, NIL);
}
}
@@ -3482,7 +3578,7 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
* If now no Vars, we must have an all-constant or all-boolean GROUP BY
* list.
*/
- if (varinfos == NIL)
+ if (exprinfos == NIL)
{
/* Apply SRF multiplier as we would do in the long path */
numdistinct *= srf_multiplier;
@@ -3506,32 +3602,32 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
*/
do
{
- GroupVarInfo *varinfo1 = (GroupVarInfo *) linitial(varinfos);
- RelOptInfo *rel = varinfo1->rel;
+ GroupExprInfo *exprinfo1 = (GroupExprInfo *) linitial(exprinfos);
+ RelOptInfo *rel = exprinfo1->rel;
double reldistinct = 1;
double relmaxndistinct = reldistinct;
int relvarcount = 0;
- List *newvarinfos = NIL;
- List *relvarinfos = NIL;
+ List *newexprinfos = NIL;
+ List *relexprinfos = NIL;
/*
* Split the list of varinfos in two - one for the current rel, one
* for remaining Vars on other rels.
*/
- relvarinfos = lappend(relvarinfos, varinfo1);
- for_each_from(l, varinfos, 1)
+ relexprinfos = lappend(relexprinfos, exprinfo1);
+ for_each_from(l, exprinfos, 1)
{
- GroupVarInfo *varinfo2 = (GroupVarInfo *) lfirst(l);
+ GroupExprInfo *exprinfo2 = (GroupExprInfo *) lfirst(l);
- if (varinfo2->rel == varinfo1->rel)
+ if (exprinfo2->rel == exprinfo1->rel)
{
/* varinfos on current rel */
- relvarinfos = lappend(relvarinfos, varinfo2);
+ relexprinfos = lappend(relexprinfos, exprinfo2);
}
else
{
- /* not time to process varinfo2 yet */
- newvarinfos = lappend(newvarinfos, varinfo2);
+ /* not time to process exprinfo2 yet */
+ newexprinfos = lappend(newexprinfos, exprinfo2);
}
}
@@ -3547,11 +3643,11 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
* apply. We apply a fudge factor below, but only if we multiplied
* more than one such values.
*/
- while (relvarinfos)
+ while (relexprinfos)
{
double mvndistinct;
- if (estimate_multivariate_ndistinct(root, rel, &relvarinfos,
+ if (estimate_multivariate_ndistinct(root, rel, &relexprinfos,
&mvndistinct))
{
reldistinct *= mvndistinct;
@@ -3561,18 +3657,24 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
}
else
{
- foreach(l, relvarinfos)
+ foreach(l, relexprinfos)
{
- GroupVarInfo *varinfo2 = (GroupVarInfo *) lfirst(l);
+ ListCell *lc;
+ GroupExprInfo *exprinfo2 = (GroupExprInfo *) lfirst(l);
+
+ foreach (lc, exprinfo2->varinfos)
+ {
+ GroupVarInfo *varinfo2 = (GroupVarInfo *) lfirst(lc);
- reldistinct *= varinfo2->ndistinct;
- if (relmaxndistinct < varinfo2->ndistinct)
- relmaxndistinct = varinfo2->ndistinct;
- relvarcount++;
+ reldistinct *= varinfo2->ndistinct;
+ if (relmaxndistinct < varinfo2->ndistinct)
+ relmaxndistinct = varinfo2->ndistinct;
+ relvarcount++;
+ }
}
/* we're done with this relation */
- relvarinfos = NIL;
+ relexprinfos = NIL;
}
}
@@ -3658,8 +3760,8 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
numdistinct *= reldistinct;
}
- varinfos = newvarinfos;
- } while (varinfos != NIL);
+ exprinfos = newexprinfos;
+ } while (exprinfos != NIL);
/* Now we can account for the effects of any SRFs */
numdistinct *= srf_multiplier;
@@ -3877,53 +3979,75 @@ estimate_hashagg_tablesize(PlannerInfo *root, Path *path,
*/
static bool
estimate_multivariate_ndistinct(PlannerInfo *root, RelOptInfo *rel,
- List **varinfos, double *ndistinct)
+ List **exprinfos, double *ndistinct)
{
ListCell *lc;
- Bitmapset *attnums = NULL;
- int nmatches;
+ int nmatches_vars;
+ int nmatches_exprs;
Oid statOid = InvalidOid;
MVNDistinct *stats;
- Bitmapset *matched = NULL;
+ StatisticExtInfo *matched_info = NULL;
/* bail out immediately if the table has no extended statistics */
if (!rel->statlist)
return false;
- /* Determine the attnums we're looking for */
- foreach(lc, *varinfos)
- {
- GroupVarInfo *varinfo = (GroupVarInfo *) lfirst(lc);
- AttrNumber attnum;
-
- Assert(varinfo->rel == rel);
-
- if (!IsA(varinfo->var, Var))
- continue;
-
- attnum = ((Var *) varinfo->var)->varattno;
-
- if (!AttrNumberIsForUserDefinedAttr(attnum))
- continue;
-
- attnums = bms_add_member(attnums, attnum);
- }
-
/* look for the ndistinct statistics matching the most vars */
- nmatches = 1; /* we require at least two matches */
+ nmatches_vars = 0; /* we require at least two matches */
+ nmatches_exprs = 0;
foreach(lc, rel->statlist)
{
+ ListCell *lc2;
StatisticExtInfo *info = (StatisticExtInfo *) lfirst(lc);
- Bitmapset *shared;
- int nshared;
+ int nshared_vars = 0;
+ int nshared_exprs = 0;
/* skip statistics of other kinds */
if (info->kind != STATS_EXT_NDISTINCT)
continue;
- /* compute attnums shared by the vars and the statistics object */
- shared = bms_intersect(info->keys, attnums);
- nshared = bms_num_members(shared);
+ /*
+ * Determine how many expressions (and variables in non-matched
+ * expressions) match.
+ */
+ foreach(lc2, *exprinfos)
+ {
+ ListCell *lc3;
+ GroupExprInfo *exprinfo = (GroupExprInfo *) lfirst(lc2);
+ AttrNumber attnum;
+
+ Assert(exprinfo->rel == rel);
+
+ /* simple Var, search in statistics keys directly */
+ if (IsA(exprinfo->expr, Var))
+ {
+ attnum = ((Var *) exprinfo->expr)->varattno;
+
+ if (!AttrNumberIsForUserDefinedAttr(attnum))
+ continue;
+
+ if (bms_is_member(attnum, info->keys))
+ nshared_vars++;
+
+ continue;
+ }
+
+ /* expression - see if it's in the statistics */
+ foreach (lc3, info->exprs)
+ {
+ Node *expr = (Node *) lfirst(lc3);
+
+ if (equal(exprinfo->expr, expr))
+ {
+ nshared_exprs++;
+ nshared_vars += list_length(exprinfo->varinfos);
+ break;
+ }
+ }
+ }
+
+ if (nshared_vars + nshared_exprs < 2)
+ continue;
/*
* Does this statistics object match more columns than the currently
@@ -3932,18 +4056,21 @@ estimate_multivariate_ndistinct(PlannerInfo *root, RelOptInfo *rel,
* XXX This should break ties using name of the object, or something
* like that, to make the outcome stable.
*/
- if (nshared > nmatches)
+ if ((nshared_vars > nmatches_vars) ||
+ ((nshared_vars == nmatches_vars) && (nshared_exprs > nmatches_exprs)))
{
statOid = info->statOid;
- nmatches = nshared;
- matched = shared;
+ nmatches_vars = nshared_vars;
+ nmatches_exprs = nshared_exprs;
+ matched_info = info;
}
}
/* No match? */
if (statOid == InvalidOid)
return false;
- Assert(nmatches > 1 && matched != NULL);
+
+ Assert(nmatches_vars + nmatches_exprs > 1);
stats = statext_ndistinct_load(statOid);
@@ -3956,6 +4083,56 @@ estimate_multivariate_ndistinct(PlannerInfo *root, RelOptInfo *rel,
int i;
List *newlist = NIL;
MVNDistinctItem *item = NULL;
+ ListCell *lc2;
+ Bitmapset *matched = NULL;
+
+ /* see what actually matched */
+ foreach (lc2, *exprinfos)
+ {
+ ListCell *lc3;
+ int idx;
+ bool found = false;
+
+ GroupExprInfo *exprinfo = (GroupExprInfo *) lfirst(lc2);
+
+ /* expression - see if it's in the statistics */
+ idx = 0;
+ foreach (lc3, matched_info->exprs)
+ {
+ Node *expr = (Node *) lfirst(lc3);
+
+ idx++;
+
+ if (equal(exprinfo->expr, expr))
+ {
+ matched = bms_add_member(matched, MaxHeapAttributeNumber + idx);
+ found = true;
+ break;
+ }
+ }
+
+ if (found)
+ continue;
+
+ foreach (lc3, exprinfo->varinfos)
+ {
+ GroupVarInfo *varinfo = (GroupVarInfo *) lfirst(lc2);
+
+ /* simple Var, search in statistics keys directly */
+ if (IsA(varinfo->var, Var))
+ {
+ AttrNumber attnum = ((Var *) varinfo->var)->varattno;
+
+ if (!AttrNumberIsForUserDefinedAttr(attnum))
+ continue;
+
+ if (!bms_is_member(attnum, matched_info->keys))
+ continue;
+
+ matched = bms_add_member(matched, attnum);
+ }
+ }
+ }
/* Find the specific item that exactly matches the combination */
for (i = 0; i < stats->nitems; i++)
@@ -3973,28 +4150,49 @@ estimate_multivariate_ndistinct(PlannerInfo *root, RelOptInfo *rel,
if (!item)
elog(ERROR, "corrupt MVNDistinct entry");
- /* Form the output varinfo list, keeping only unmatched ones */
- foreach(lc, *varinfos)
+ /* Form the output exprinfo list, keeping only unmatched ones */
+ foreach(lc, *exprinfos)
{
- GroupVarInfo *varinfo = (GroupVarInfo *) lfirst(lc);
+ GroupExprInfo *exprinfo = (GroupExprInfo *) lfirst(lc);
AttrNumber attnum;
+ ListCell *lc3;
+ bool found = false;
+
+ foreach (lc3, matched_info->exprs)
+ {
+ Node *expr = (Node *) lfirst(lc3);
+
+ if (equal(exprinfo->expr, expr))
+ {
+ found = true;
+ break;
+ }
+ }
+
+ /* the whole expression was matched, so skip it */
+ if (found)
+ continue;
- if (!IsA(varinfo->var, Var))
+ if (!IsA(exprinfo->expr, Var))
{
- newlist = lappend(newlist, varinfo);
+ /*
+ * FIXME Probably should remove varinfos that match the
+ * selected MVNDistinct item.
+ */
+ newlist = lappend(newlist, exprinfo);
continue;
}
- attnum = ((Var *) varinfo->var)->varattno;
+ attnum = ((Var *) exprinfo->expr)->varattno;
if (!AttrNumberIsForUserDefinedAttr(attnum))
continue;
if (!bms_is_member(attnum, matched))
- newlist = lappend(newlist, varinfo);
+ newlist = lappend(newlist, exprinfo);
}
- *varinfos = newlist;
+ *exprinfos = newlist;
*ndistinct = item->ndistinct;
return true;
}
@@ -4690,6 +4888,13 @@ get_join_variables(PlannerInfo *root, List *args, SpecialJoinInfo *sjinfo,
*join_is_reversed = false;
}
+/* statext_expressions_load copies the tuple, so just pfree it. */
+static void
+ReleaseDummy(HeapTuple tuple)
+{
+ pfree(tuple);
+}
+
/*
* examine_variable
* Try to look up statistical data about an expression.
@@ -4830,6 +5035,7 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
* operator we are estimating for. FIXME later.
*/
ListCell *ilist;
+ ListCell *slist;
foreach(ilist, onerel->indexlist)
{
@@ -4986,6 +5192,68 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
if (vardata->statsTuple)
break;
}
+
+ /*
+ * Search extended statistics for one with a matching expression.
+ * There might be multiple ones, so just grab the first one. In
+ * the future, we might consider the statistics target (and pick
+ * the most accurate statistics) and maybe some other parameters.
+ */
+ foreach(slist, onerel->statlist)
+ {
+ StatisticExtInfo *info = (StatisticExtInfo *) lfirst(slist);
+ ListCell *expr_item;
+ int pos;
+
+ /*
+ * Stop once we've found statistics for the expression (either
+ * from extended stats, or for an index in the preceding loop).
+ */
+ if (vardata->statsTuple)
+ break;
+
+ /* skip stats without per-expression stats */
+ if (info->kind != STATS_EXT_EXPRESSIONS)
+ continue;
+
+ pos = 0;
+ foreach (expr_item, info->exprs)
+ {
+ Node *expr = (Node *) lfirst(expr_item);
+
+ Assert(expr);
+
+ /* strip RelabelType before comparing it */
+ if (expr && IsA(expr, RelabelType))
+ expr = (Node *) ((RelabelType *) expr)->arg;
+
+ /* found a match, see if we can extract pg_statistic row */
+ if (equal(node, expr))
+ {
+ HeapTuple t = statext_expressions_load(info->statOid, pos);
+
+ vardata->statsTuple = t;
+
+ /*
+ * FIXME not sure if we should cache the tuple somewhere?
+ * It's stored in a cached tuple in the "data" catalog,
+ * and we just create a new copy every time.
+ */
+ vardata->freefunc = ReleaseDummy;
+
+ /*
+ * FIXME Hack to make statistic_proc_security_check happy,
+ * so that this does not get rejected. Probably needs more
+ * thought, just a hack.
+ */
+ vardata->acl_ok = true;
+
+ break;
+ }
+
+ pos++;
+ }
+ }
}
}
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 2b501166b8..23cc23d037 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -2591,6 +2591,18 @@ my %tests = (
unlike => { exclude_dump_test_schema => 1, },
},
+ 'CREATE STATISTICS extended_stats_expression' => {
+ create_order => 99,
+ create_sql => 'CREATE STATISTICS dump_test.test_ext_stats_expr
+ ON (2 * col1) FROM dump_test.test_fifth_table',
+ regexp => qr/^
+ \QCREATE STATISTICS dump_test.test_ext_stats_expr ON ((2 * col1)) FROM dump_test.test_fifth_table;\E
+ /xms,
+ like =>
+ { %full_runs, %dump_test_schema_runs, section_post_data => 1, },
+ unlike => { exclude_dump_test_schema => 1, },
+ },
+
'CREATE SEQUENCE test_table_col1_seq' => {
regexp => qr/^
\QCREATE SEQUENCE dump_test.test_table_col1_seq\E
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index caf97563f4..244bbb5f82 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2680,15 +2680,16 @@ describeOneTableDetails(const char *schemaname,
/* print any extended statistics */
if (pset.sversion >= 100000)
{
+ /*
+ * FIXME this needs to be version-dependent, because older
+ * versions don't have pg_get_statisticsobjdef_columns.
+ */
printfPQExpBuffer(&buf,
"SELECT oid, "
"stxrelid::pg_catalog.regclass, "
"stxnamespace::pg_catalog.regnamespace AS nsp, "
"stxname,\n"
- " (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(attname),', ')\n"
- " FROM pg_catalog.unnest(stxkeys) s(attnum)\n"
- " JOIN pg_catalog.pg_attribute a ON (stxrelid = a.attrelid AND\n"
- " a.attnum = s.attnum AND NOT attisdropped)) AS columns,\n"
+ "pg_get_statisticsobjdef_columns(oid) AS columns,\n"
" 'd' = any(stxkind) AS ndist_enabled,\n"
" 'f' = any(stxkind) AS deps_enabled,\n"
" 'm' = any(stxkind) AS mcv_enabled,\n");
@@ -2715,33 +2716,60 @@ describeOneTableDetails(const char *schemaname,
for (i = 0; i < tuples; i++)
{
bool gotone = false;
+ bool has_ndistinct;
+ bool has_dependencies;
+ bool has_mcv;
+ bool has_all;
+ bool has_some;
+
+ has_ndistinct = (strcmp(PQgetvalue(result, i, 5), "t") == 0);
+ has_dependencies = (strcmp(PQgetvalue(result, i, 6), "t") == 0);
+ has_mcv = (strcmp(PQgetvalue(result, i, 7), "t") == 0);
printfPQExpBuffer(&buf, " ");
/* statistics object name (qualified with namespace) */
- appendPQExpBuffer(&buf, "\"%s\".\"%s\" (",
+ appendPQExpBuffer(&buf, "\"%s\".\"%s\"",
PQgetvalue(result, i, 2),
PQgetvalue(result, i, 3));
- /* options */
- if (strcmp(PQgetvalue(result, i, 5), "t") == 0)
- {
- appendPQExpBufferStr(&buf, "ndistinct");
- gotone = true;
- }
+ /*
+ * When printing kinds we ignore expression statistics, which
+ * is used only internally and can't be specified by user.
+ * We don't print the kinds when either none are specified
+ * (in which case it has to be statistics on a single expr)
+ * or when all are specified (in which case we assume it's
+ * expanded by CREATE STATISTICS).
+ */
+ has_all = (has_ndistinct && has_dependencies && has_mcv);
+ has_some = (has_ndistinct || has_dependencies || has_mcv);
- if (strcmp(PQgetvalue(result, i, 6), "t") == 0)
+ if (has_some && !has_all)
{
- appendPQExpBuffer(&buf, "%sdependencies", gotone ? ", " : "");
- gotone = true;
- }
+ appendPQExpBuffer(&buf, " (");
- if (strcmp(PQgetvalue(result, i, 7), "t") == 0)
- {
- appendPQExpBuffer(&buf, "%smcv", gotone ? ", " : "");
+ /* options */
+ if (has_ndistinct)
+ {
+ appendPQExpBufferStr(&buf, "ndistinct");
+ gotone = true;
+ }
+
+ if (has_dependencies)
+ {
+ appendPQExpBuffer(&buf, "%sdependencies", gotone ? ", " : "");
+ gotone = true;
+ }
+
+ if (has_mcv)
+ {
+ appendPQExpBuffer(&buf, "%smcv", gotone ? ", " : "");
+ }
+
+ appendPQExpBuffer(&buf, ")");
}
- appendPQExpBuffer(&buf, ") ON %s FROM %s",
+ appendPQExpBuffer(&buf, " ON %s FROM %s",
PQgetvalue(result, i, 4),
PQgetvalue(result, i, 1));
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index d27336adcd..0c9b78302b 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -3652,6 +3652,14 @@
proname => 'pg_get_statisticsobjdef', provolatile => 's',
prorettype => 'text', proargtypes => 'oid',
prosrc => 'pg_get_statisticsobjdef' },
+{ oid => '8887', descr => 'extended statistics columns',
+ proname => 'pg_get_statisticsobjdef_columns', provolatile => 's',
+ prorettype => 'text', proargtypes => 'oid',
+ prosrc => 'pg_get_statisticsobjdef_columns' },
+{ oid => '8886', descr => 'extended statistics expressions',
+ proname => 'pg_get_statisticsobjdef_expressions', provolatile => 's',
+ prorettype => '_text', proargtypes => 'oid',
+ prosrc => 'pg_get_statisticsobjdef_expressions' },
{ oid => '3352', descr => 'partition key description',
proname => 'pg_get_partkeydef', provolatile => 's', prorettype => 'text',
proargtypes => 'oid', prosrc => 'pg_get_partkeydef' },
diff --git a/src/include/catalog/pg_statistic_ext.h b/src/include/catalog/pg_statistic_ext.h
index 99f6cea0a5..cf46a79af9 100644
--- a/src/include/catalog/pg_statistic_ext.h
+++ b/src/include/catalog/pg_statistic_ext.h
@@ -52,6 +52,9 @@ CATALOG(pg_statistic_ext,3381,StatisticExtRelationId)
#ifdef CATALOG_VARLEN
char stxkind[1] BKI_FORCE_NOT_NULL; /* statistics kinds requested
* to build */
+ pg_node_tree stxexprs; /* A list of expression trees for stats
+ * attributes that are not simple column
+ * references. */
#endif
} FormData_pg_statistic_ext;
@@ -77,6 +80,7 @@ DECLARE_INDEX(pg_statistic_ext_relid_index, 3379, on pg_statistic_ext using btre
#define STATS_EXT_NDISTINCT 'd'
#define STATS_EXT_DEPENDENCIES 'f'
#define STATS_EXT_MCV 'm'
+#define STATS_EXT_EXPRESSIONS 'e'
#endif /* EXPOSE_TO_CLIENT_CODE */
diff --git a/src/include/catalog/pg_statistic_ext_data.h b/src/include/catalog/pg_statistic_ext_data.h
index e0aa152f7b..0d2f6a6c32 100644
--- a/src/include/catalog/pg_statistic_ext_data.h
+++ b/src/include/catalog/pg_statistic_ext_data.h
@@ -37,6 +37,7 @@ CATALOG(pg_statistic_ext_data,3429,StatisticExtDataRelationId)
pg_ndistinct stxdndistinct; /* ndistinct coefficients (serialized) */
pg_dependencies stxddependencies; /* dependencies (serialized) */
pg_mcv_list stxdmcv; /* MCV (serialized) */
+ pg_statistic stxdexpr[1]; /* stats for expressions */
#endif
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index caed683ba9..374f047dda 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.h
@@ -451,6 +451,7 @@ typedef enum NodeTag
T_TypeName,
T_ColumnDef,
T_IndexElem,
+ T_StatsElem,
T_Constraint,
T_DefElem,
T_RangeTblEntry,
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index dc2bb40926..f2042ba445 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2830,8 +2830,24 @@ typedef struct CreateStatsStmt
List *relations; /* rels to build stats on (list of RangeVar) */
char *stxcomment; /* comment to apply to stats, or NULL */
bool if_not_exists; /* do nothing if stats name already exists */
+ bool transformed; /* true when transformStatsStmt is finished */
} CreateStatsStmt;
+/*
+ * StatsElem - statistics parameters (used in CREATE STATISTICS)
+ *
+ * For a plain attribute, 'name' is the name of the referenced table column
+ * and 'expr' is NULL. For an expression, 'name' is NULL and 'expr' is the
+ * expression tree.
+ */
+typedef struct StatsElem
+{
+ NodeTag type;
+ char *name; /* name of attribute to index, or NULL */
+ Node *expr; /* expression to index, or NULL */
+} StatsElem;
+
+
/* ----------------------
* Alter Statistics Statement
* ----------------------
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index cde2637798..c384f2c6e7 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -915,8 +915,9 @@ typedef struct StatisticExtInfo
Oid statOid; /* OID of the statistics row */
RelOptInfo *rel; /* back-link to statistic's table */
- char kind; /* statistic kind of this entry */
+ char kind; /* statistics kind of this entry */
Bitmapset *keys; /* attnums of the columns covered */
+ List *exprs; /* expressions */
} StatisticExtInfo;
/*
diff --git a/src/include/parser/parse_node.h b/src/include/parser/parse_node.h
index dfc214b06f..2b477c38eb 100644
--- a/src/include/parser/parse_node.h
+++ b/src/include/parser/parse_node.h
@@ -69,6 +69,7 @@ typedef enum ParseExprKind
EXPR_KIND_FUNCTION_DEFAULT, /* default parameter value for function */
EXPR_KIND_INDEX_EXPRESSION, /* index expression */
EXPR_KIND_INDEX_PREDICATE, /* index predicate */
+ EXPR_KIND_STATS_EXPRESSION, /* extended statistics expression */
EXPR_KIND_ALTER_COL_TRANSFORM, /* transform expr in ALTER COLUMN TYPE */
EXPR_KIND_EXECUTE_PARAMETER, /* parameter value in EXECUTE */
EXPR_KIND_TRIGGER_WHEN, /* WHEN condition in CREATE TRIGGER */
diff --git a/src/include/parser/parse_utilcmd.h b/src/include/parser/parse_utilcmd.h
index bfa4a6b0f2..1056bf081b 100644
--- a/src/include/parser/parse_utilcmd.h
+++ b/src/include/parser/parse_utilcmd.h
@@ -26,6 +26,8 @@ extern AlterTableStmt *transformAlterTableStmt(Oid relid, AlterTableStmt *stmt,
List **afterStmts);
extern IndexStmt *transformIndexStmt(Oid relid, IndexStmt *stmt,
const char *queryString);
+extern CreateStatsStmt *transformStatsStmt(Oid relid, CreateStatsStmt *stmt,
+ const char *queryString);
extern void transformRuleStmt(RuleStmt *stmt, const char *queryString,
List **actions, Node **whereClause);
extern List *transformCreateSchemaStmt(CreateSchemaStmt *stmt);
diff --git a/src/include/statistics/extended_stats_internal.h b/src/include/statistics/extended_stats_internal.h
index c849bd57c0..092bc3eb8a 100644
--- a/src/include/statistics/extended_stats_internal.h
+++ b/src/include/statistics/extended_stats_internal.h
@@ -57,19 +57,35 @@ typedef struct SortItem
int count;
} SortItem;
+/*
+ * Used to pass pre-computed information about expressions the stats
+ * object is defined on.
+ */
+typedef struct ExprInfo
+{
+ int nexprs; /* number of expressions */
+ Oid *collations; /* collation for each expression */
+ Oid *types; /* type of each expression */
+ Datum **values; /* values for each expression */
+ bool **nulls; /* nulls for each expression */
+} ExprInfo;
+
extern MVNDistinct *statext_ndistinct_build(double totalrows,
int numrows, HeapTuple *rows,
- Bitmapset *attrs, VacAttrStats **stats);
+ ExprInfo *exprs, Bitmapset *attrs,
+ VacAttrStats **stats);
extern bytea *statext_ndistinct_serialize(MVNDistinct *ndistinct);
extern MVNDistinct *statext_ndistinct_deserialize(bytea *data);
extern MVDependencies *statext_dependencies_build(int numrows, HeapTuple *rows,
- Bitmapset *attrs, VacAttrStats **stats);
+ ExprInfo *exprs, Bitmapset *attrs,
+ VacAttrStats **stats);
extern bytea *statext_dependencies_serialize(MVDependencies *dependencies);
extern MVDependencies *statext_dependencies_deserialize(bytea *data);
extern MCVList *statext_mcv_build(int numrows, HeapTuple *rows,
- Bitmapset *attrs, VacAttrStats **stats,
+ ExprInfo *exprs, Bitmapset *attrs,
+ VacAttrStats **stats,
double totalrows, int stattarget);
extern bytea *statext_mcv_serialize(MCVList *mcv, VacAttrStats **stats);
extern MCVList *statext_mcv_deserialize(bytea *data);
@@ -93,11 +109,18 @@ extern void *bsearch_arg(const void *key, const void *base,
extern AttrNumber *build_attnums_array(Bitmapset *attrs, int *numattrs);
extern SortItem *build_sorted_items(int numrows, int *nitems, HeapTuple *rows,
- TupleDesc tdesc, MultiSortSupport mss,
+ ExprInfo *exprs, TupleDesc tdesc,
+ MultiSortSupport mss,
int numattrs, AttrNumber *attnums);
extern bool examine_clause_args(List *args, Var **varp,
Const **cstp, bool *varonleftp);
+extern bool examine_clause_args2(List *args, Node **exprp,
+ Const **cstp, bool *expronleftp);
+extern bool examine_opclause_expression(OpExpr *expr, Var **varp, Const **cstp,
+ bool *varonleftp);
+extern bool examine_opclause_expression2(OpExpr *expr, Node **exprp, Const **cstp,
+ bool *expronleftp);
extern Selectivity mcv_combine_selectivities(Selectivity simple_sel,
Selectivity mcv_sel,
@@ -124,4 +147,13 @@ extern Selectivity mcv_clause_selectivity_or(PlannerInfo *root,
Selectivity *overlap_basesel,
Selectivity *totalsel);
+extern Bitmapset *add_expressions_to_attributes(Bitmapset *attrs, int nexprs);
+
+/* translate 0-based expression index to attnum and back */
+#define EXPRESSION_ATTNUM(index) \
+ (MaxHeapAttributeNumber + (index) + 1)
+
+#define EXPRESSION_INDEX(attnum) \
+ ((attnum) - MaxHeapAttributeNumber - 1)
+
#endif /* EXTENDED_STATS_INTERNAL_H */
diff --git a/src/include/statistics/statistics.h b/src/include/statistics/statistics.h
index fec50688ea..006d578e0c 100644
--- a/src/include/statistics/statistics.h
+++ b/src/include/statistics/statistics.h
@@ -121,6 +121,8 @@ extern Selectivity statext_clauselist_selectivity(PlannerInfo *root,
extern bool has_stats_of_kind(List *stats, char requiredkind);
extern StatisticExtInfo *choose_best_statistics(List *stats, char requiredkind,
Bitmapset **clause_attnums,
+ List **clause_exprs,
int nclauses);
+extern HeapTuple statext_expressions_load(Oid stxoid, int idx);
#endif /* STATISTICS_H */
diff --git a/src/test/regress/expected/create_table_like.out b/src/test/regress/expected/create_table_like.out
index 10d17be23c..4dc5e6aa5f 100644
--- a/src/test/regress/expected/create_table_like.out
+++ b/src/test/regress/expected/create_table_like.out
@@ -304,7 +304,9 @@ CREATE TABLE ctlt1 (a text CHECK (length(a) > 2) PRIMARY KEY, b text);
CREATE INDEX ctlt1_b_key ON ctlt1 (b);
CREATE INDEX ctlt1_fnidx ON ctlt1 ((a || b));
CREATE STATISTICS ctlt1_a_b_stat ON a,b FROM ctlt1;
+CREATE STATISTICS ctlt1_expr_stat ON (a || b) FROM ctlt1;
COMMENT ON STATISTICS ctlt1_a_b_stat IS 'ab stats';
+COMMENT ON STATISTICS ctlt1_expr_stat IS 'ab expr stats';
COMMENT ON COLUMN ctlt1.a IS 'A';
COMMENT ON COLUMN ctlt1.b IS 'B';
COMMENT ON CONSTRAINT ctlt1_a_check ON ctlt1 IS 't1_a_check';
@@ -414,7 +416,8 @@ Indexes:
Check constraints:
"ctlt1_a_check" CHECK (length(a) > 2)
Statistics objects:
- "public"."ctlt_all_a_b_stat" (ndistinct, dependencies, mcv) ON a, b FROM ctlt_all
+ "public"."ctlt_all_a_b_stat" ON a, b FROM ctlt_all
+ "public"."ctlt_all_expr_stat" ON ((a || b)) FROM ctlt_all
SELECT c.relname, objsubid, description FROM pg_description, pg_index i, pg_class c WHERE classoid = 'pg_class'::regclass AND objoid = i.indexrelid AND c.oid = i.indexrelid AND i.indrelid = 'ctlt_all'::regclass ORDER BY c.relname, objsubid;
relname | objsubid | description
@@ -424,10 +427,11 @@ SELECT c.relname, objsubid, description FROM pg_description, pg_index i, pg_clas
(2 rows)
SELECT s.stxname, objsubid, description FROM pg_description, pg_statistic_ext s WHERE classoid = 'pg_statistic_ext'::regclass AND objoid = s.oid AND s.stxrelid = 'ctlt_all'::regclass ORDER BY s.stxname, objsubid;
- stxname | objsubid | description
--------------------+----------+-------------
- ctlt_all_a_b_stat | 0 | ab stats
-(1 row)
+ stxname | objsubid | description
+--------------------+----------+---------------
+ ctlt_all_a_b_stat | 0 | ab stats
+ ctlt_all_expr_stat | 0 | ab expr stats
+(2 rows)
CREATE TABLE inh_error1 () INHERITS (ctlt1, ctlt4);
NOTICE: merging multiple inherited definitions of column "a"
@@ -452,7 +456,8 @@ Indexes:
Check constraints:
"ctlt1_a_check" CHECK (length(a) > 2)
Statistics objects:
- "public"."pg_attrdef_a_b_stat" (ndistinct, dependencies, mcv) ON a, b FROM public.pg_attrdef
+ "public"."pg_attrdef_a_b_stat" ON a, b FROM public.pg_attrdef
+ "public"."pg_attrdef_expr_stat" ON ((a || b)) FROM public.pg_attrdef
DROP TABLE public.pg_attrdef;
-- Check that LIKE isn't confused when new table masks the old, either
@@ -473,7 +478,8 @@ Indexes:
Check constraints:
"ctlt1_a_check" CHECK (length(a) > 2)
Statistics objects:
- "ctl_schema"."ctlt1_a_b_stat" (ndistinct, dependencies, mcv) ON a, b FROM ctlt1
+ "ctl_schema"."ctlt1_a_b_stat" ON a, b FROM ctlt1
+ "ctl_schema"."ctlt1_expr_stat" ON ((a || b)) FROM ctlt1
ROLLBACK;
DROP TABLE ctlt1, ctlt2, ctlt3, ctlt4, ctlt12_storage, ctlt12_comments, ctlt1_inh, ctlt13_inh, ctlt13_like, ctlt_all, ctla, ctlb CASCADE;
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index a687e99d1e..663cb7b150 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -2393,6 +2393,7 @@ pg_stats_ext| SELECT cn.nspname AS schemaname,
( SELECT array_agg(a.attname ORDER BY a.attnum) AS array_agg
FROM (unnest(s.stxkeys) k(k)
JOIN pg_attribute a ON (((a.attrelid = s.stxrelid) AND (a.attnum = k.k))))) AS attnames,
+ pg_get_statisticsobjdef_expressions(s.oid) AS exprs,
s.stxkind AS kinds,
sd.stxdndistinct AS n_distinct,
sd.stxddependencies AS dependencies,
@@ -2414,6 +2415,80 @@ pg_stats_ext| SELECT cn.nspname AS schemaname,
FROM (unnest(s.stxkeys) k(k)
JOIN pg_attribute a ON (((a.attrelid = s.stxrelid) AND (a.attnum = k.k))))
WHERE (NOT has_column_privilege(c.oid, a.attnum, 'select'::text))))) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
+pg_stats_ext_exprs| SELECT cn.nspname AS schemaname,
+ c.relname AS tablename,
+ sn.nspname AS statistics_schemaname,
+ s.stxname AS statistics_name,
+ pg_get_userbyid(s.stxowner) AS statistics_owner,
+ stat.expr,
+ (stat.a).stanullfrac AS null_frac,
+ (stat.a).stawidth AS avg_width,
+ (stat.a).stadistinct AS n_distinct,
+ CASE
+ WHEN ((stat.a).stakind1 = 1) THEN (stat.a).stavalues1
+ WHEN ((stat.a).stakind2 = 1) THEN (stat.a).stavalues2
+ WHEN ((stat.a).stakind3 = 1) THEN (stat.a).stavalues3
+ WHEN ((stat.a).stakind4 = 1) THEN (stat.a).stavalues4
+ WHEN ((stat.a).stakind5 = 1) THEN (stat.a).stavalues5
+ ELSE NULL::anyarray
+ END AS most_common_vals,
+ CASE
+ WHEN ((stat.a).stakind1 = 1) THEN (stat.a).stanumbers1
+ WHEN ((stat.a).stakind2 = 1) THEN (stat.a).stanumbers2
+ WHEN ((stat.a).stakind3 = 1) THEN (stat.a).stanumbers3
+ WHEN ((stat.a).stakind4 = 1) THEN (stat.a).stanumbers4
+ WHEN ((stat.a).stakind5 = 1) THEN (stat.a).stanumbers5
+ ELSE NULL::real[]
+ END AS most_common_freqs,
+ CASE
+ WHEN ((stat.a).stakind1 = 2) THEN (stat.a).stavalues1
+ WHEN ((stat.a).stakind2 = 2) THEN (stat.a).stavalues2
+ WHEN ((stat.a).stakind3 = 2) THEN (stat.a).stavalues3
+ WHEN ((stat.a).stakind4 = 2) THEN (stat.a).stavalues4
+ WHEN ((stat.a).stakind5 = 2) THEN (stat.a).stavalues5
+ ELSE NULL::anyarray
+ END AS histogram_bounds,
+ CASE
+ WHEN ((stat.a).stakind1 = 3) THEN (stat.a).stanumbers1[1]
+ WHEN ((stat.a).stakind2 = 3) THEN (stat.a).stanumbers2[1]
+ WHEN ((stat.a).stakind3 = 3) THEN (stat.a).stanumbers3[1]
+ WHEN ((stat.a).stakind4 = 3) THEN (stat.a).stanumbers4[1]
+ WHEN ((stat.a).stakind5 = 3) THEN (stat.a).stanumbers5[1]
+ ELSE NULL::real
+ END AS correlation,
+ CASE
+ WHEN ((stat.a).stakind1 = 4) THEN (stat.a).stavalues1
+ WHEN ((stat.a).stakind2 = 4) THEN (stat.a).stavalues2
+ WHEN ((stat.a).stakind3 = 4) THEN (stat.a).stavalues3
+ WHEN ((stat.a).stakind4 = 4) THEN (stat.a).stavalues4
+ WHEN ((stat.a).stakind5 = 4) THEN (stat.a).stavalues5
+ ELSE NULL::anyarray
+ END AS most_common_elems,
+ CASE
+ WHEN ((stat.a).stakind1 = 4) THEN (stat.a).stanumbers1
+ WHEN ((stat.a).stakind2 = 4) THEN (stat.a).stanumbers2
+ WHEN ((stat.a).stakind3 = 4) THEN (stat.a).stanumbers3
+ WHEN ((stat.a).stakind4 = 4) THEN (stat.a).stanumbers4
+ WHEN ((stat.a).stakind5 = 4) THEN (stat.a).stanumbers5
+ ELSE NULL::real[]
+ END AS most_common_elem_freqs,
+ CASE
+ WHEN ((stat.a).stakind1 = 5) THEN (stat.a).stanumbers1
+ WHEN ((stat.a).stakind2 = 5) THEN (stat.a).stanumbers2
+ WHEN ((stat.a).stakind3 = 5) THEN (stat.a).stanumbers3
+ WHEN ((stat.a).stakind4 = 5) THEN (stat.a).stanumbers4
+ WHEN ((stat.a).stakind5 = 5) THEN (stat.a).stanumbers5
+ ELSE NULL::real[]
+ END AS elem_count_histogram
+ FROM (((((pg_statistic_ext s
+ JOIN pg_class c ON ((c.oid = s.stxrelid)))
+ JOIN pg_statistic_ext_data sd ON ((s.oid = sd.stxoid)))
+ LEFT JOIN pg_namespace cn ON ((cn.oid = c.relnamespace)))
+ LEFT JOIN pg_namespace sn ON ((sn.oid = s.stxnamespace)))
+ LEFT JOIN LATERAL ( SELECT x.expr,
+ x.a
+ FROM ( SELECT unnest(pg_get_statisticsobjdef_expressions(s.oid)) AS expr,
+ unnest(sd.stxdexpr) AS a) x) stat ON ((sd.stxdexpr IS NOT NULL)));
pg_tables| SELECT n.nspname AS schemaname,
c.relname AS tablename,
pg_get_userbyid(c.relowner) AS tableowner,
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index f094731e32..71a0eb74e3 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -25,7 +25,7 @@ begin
end;
$$;
-- Verify failures
-CREATE TABLE ext_stats_test (x int, y int, z int);
+CREATE TABLE ext_stats_test (x text, y int, z int);
CREATE STATISTICS tst;
ERROR: syntax error at or near ";"
LINE 1: CREATE STATISTICS tst;
@@ -44,12 +44,25 @@ CREATE STATISTICS tst ON a, b FROM ext_stats_test;
ERROR: column "a" does not exist
CREATE STATISTICS tst ON x, x, y FROM ext_stats_test;
ERROR: duplicate column name in statistics definition
-CREATE STATISTICS tst ON x + y FROM ext_stats_test;
-ERROR: only simple column references are allowed in CREATE STATISTICS
-CREATE STATISTICS tst ON (x, y) FROM ext_stats_test;
-ERROR: only simple column references are allowed in CREATE STATISTICS
+CREATE STATISTICS tst ON x, x, y, x, x, y, x, x, y FROM ext_stats_test;
+ERROR: cannot have more than 8 columns in statistics
+CREATE STATISTICS tst ON x, x, y, x, x, (x || 'x'), (y + 1), (x || 'x'), (x || 'x'), (y + 1) FROM ext_stats_test;
+ERROR: cannot have more than 8 columns in statistics
+CREATE STATISTICS tst ON (x || 'x'), (x || 'x'), (y + 1), (x || 'x'), (x || 'x'), (y + 1), (x || 'x'), (x || 'x'), (y + 1) FROM ext_stats_test;
+ERROR: cannot have more than 8 columns in statistics
+CREATE STATISTICS tst ON (x || 'x'), (x || 'x'), y FROM ext_stats_test;
+ERROR: duplicate expression in statistics definition
CREATE STATISTICS tst (unrecognized) ON x, y FROM ext_stats_test;
ERROR: unrecognized statistics kind "unrecognized"
+-- incorrect expressions
+CREATE STATISTICS tst ON y + z FROM ext_stats_test; -- missing parentheses
+ERROR: syntax error at or near "+"
+LINE 1: CREATE STATISTICS tst ON y + z FROM ext_stats_test;
+ ^
+CREATE STATISTICS tst ON (x, y) FROM ext_stats_test; -- tuple expression
+ERROR: syntax error at or near ","
+LINE 1: CREATE STATISTICS tst ON (x, y) FROM ext_stats_test;
+ ^
DROP TABLE ext_stats_test;
-- Ensure stats are dropped sanely, and test IF NOT EXISTS while at it
CREATE TABLE ab1 (a INTEGER, b INTEGER, c INTEGER);
@@ -79,7 +92,7 @@ ALTER TABLE ab1 DROP COLUMN a;
b | integer | | |
c | integer | | |
Statistics objects:
- "public"."ab1_b_c_stats" (ndistinct, dependencies, mcv) ON b, c FROM ab1
+ "public"."ab1_b_c_stats" ON b, c FROM ab1
-- Ensure statistics are dropped when table is
SELECT stxname FROM pg_statistic_ext WHERE stxname LIKE 'ab1%';
@@ -111,7 +124,7 @@ ALTER STATISTICS ab1_a_b_stats SET STATISTICS 0;
a | integer | | |
b | integer | | |
Statistics objects:
- "public"."ab1_a_b_stats" (ndistinct, dependencies, mcv) ON a, b FROM ab1; STATISTICS 0
+ "public"."ab1_a_b_stats" ON a, b FROM ab1; STATISTICS 0
ANALYZE ab1;
SELECT stxname, stxdndistinct, stxddependencies, stxdmcv
@@ -131,7 +144,7 @@ ALTER STATISTICS ab1_a_b_stats SET STATISTICS -1;
a | integer | | | | plain | |
b | integer | | | | plain | |
Statistics objects:
- "public"."ab1_a_b_stats" (ndistinct, dependencies, mcv) ON a, b FROM ab1
+ "public"."ab1_a_b_stats" ON a, b FROM ab1
-- partial analyze doesn't build stats either
ANALYZE ab1 (a);
@@ -150,6 +163,39 @@ CREATE STATISTICS ab1_a_b_stats ON a, b FROM ab1;
ANALYZE ab1;
DROP TABLE ab1 CASCADE;
NOTICE: drop cascades to table ab1c
+-- basic test for statistics on expressions
+CREATE TABLE ab1 (a INTEGER, b INTEGER, c TIMESTAMP, d TIMESTAMPTZ);
+-- expression stats may be built on a single expression column
+CREATE STATISTICS ab1_exprstat_1 ON (a+b) FROM ab1;
+-- with a single expression, we only enable expression statistics
+CREATE STATISTICS ab1_exprstat_2 ON (a+b) FROM ab1;
+SELECT stxkind FROM pg_statistic_ext WHERE stxname = 'ab1_exprstat_2';
+ stxkind
+---------
+ {e}
+(1 row)
+
+-- adding anything to the expression builds all statistics kinds
+CREATE STATISTICS ab1_exprstat_3 ON (a+b), a FROM ab1;
+SELECT stxkind FROM pg_statistic_ext WHERE stxname = 'ab1_exprstat_3';
+ stxkind
+-----------
+ {d,f,m,e}
+(1 row)
+
+-- expression must be immutable, but date_trunc on timestamptz is not
+CREATE STATISTICS ab1_exprstat_4 ON date_trunc('day', d) FROM ab1;
+-- but on timestamp it should work fine
+CREATE STATISTICS ab1_exprstat_5 ON date_trunc('day', c) FROM ab1;
+-- insert some data and run analyze, to test that these cases build properly
+INSERT INTO ab1
+SELECT
+ generate_series(1,10),
+ generate_series(1,10),
+ generate_series('2020-10-01'::timestamp, '2020-10-10'::timestamp, interval '1 day'),
+ generate_series('2020-10-01'::timestamptz, '2020-10-10'::timestamptz, interval '1 day');
+ANALYZE ab1;
+DROP TABLE ab1;
-- Verify supported object types for extended statistics
CREATE schema tststats;
CREATE TABLE tststats.t (a int, b int, c text);
@@ -427,6 +473,40 @@ SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE
1 | 1
(1 row)
+-- a => b, a => c, b => c
+TRUNCATE functional_dependencies;
+DROP STATISTICS func_deps_stat;
+-- now do the same thing, but with expressions
+INSERT INTO functional_dependencies (a, b, c, filler1)
+ SELECT i, i, i, i FROM generate_series(1,5000) s(i);
+ANALYZE functional_dependencies;
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1');
+ estimated | actual
+-----------+--------
+ 1 | 35
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1 AND mod(c, 7) = 1');
+ estimated | actual
+-----------+--------
+ 1 | 5
+(1 row)
+
+-- create statistics
+CREATE STATISTICS func_deps_stat (dependencies) ON (mod(a,11)), (mod(b::int, 13)), (mod(c, 7)) FROM functional_dependencies;
+ANALYZE functional_dependencies;
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1');
+ estimated | actual
+-----------+--------
+ 35 | 35
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1 AND mod(c, 7) = 1');
+ estimated | actual
+-----------+--------
+ 5 | 5
+(1 row)
+
-- a => b, a => c, b => c
TRUNCATE functional_dependencies;
DROP STATISTICS func_deps_stat;
@@ -896,6 +976,39 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b =
1 | 1
(1 row)
+TRUNCATE mcv_lists;
+DROP STATISTICS mcv_lists_stats;
+-- random data (no MCV list), but with expression
+INSERT INTO mcv_lists (a, b, c, filler1)
+ SELECT i, i, i, i FROM generate_series(1,5000) s(i);
+ANALYZE mcv_lists;
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,37) = 1 AND mod(b::int,41) = 1');
+ estimated | actual
+-----------+--------
+ 1 | 4
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,37) = 1 AND mod(b::int,41) = 1 AND mod(c,47) = 1');
+ estimated | actual
+-----------+--------
+ 1 | 1
+(1 row)
+
+-- create statistics
+CREATE STATISTICS mcv_lists_stats (mcv) ON (mod(a,37)), (mod(b::int,41)), (mod(c,47)) FROM mcv_lists;
+ANALYZE mcv_lists;
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,37) = 1 AND mod(b::int,41) = 1');
+ estimated | actual
+-----------+--------
+ 3 | 4
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,37) = 1 AND mod(b::int,41) = 1 AND mod(c,47) = 1');
+ estimated | actual
+-----------+--------
+ 1 | 1
+(1 row)
+
-- 100 distinct combinations, all in the MCV list
TRUNCATE mcv_lists;
DROP STATISTICS mcv_lists_stats;
@@ -1121,6 +1234,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
200 | 200
(1 row)
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
+ estimated | actual
+-----------+--------
+ 200 | 200
+(1 row)
+
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (1, 2, 51, 52) AND b IN ( ''1'', ''2'')');
estimated | actual
-----------+--------
@@ -1207,6 +1326,458 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b =
50 | 50
(1 row)
+-- 100 distinct combinations, all in the MCV list, but with expressions
+TRUNCATE mcv_lists;
+DROP STATISTICS mcv_lists_stats;
+INSERT INTO mcv_lists (a, b, c, filler1)
+ SELECT i, i, i, i FROM generate_series(1,5000) s(i);
+ANALYZE mcv_lists;
+-- without any stats on the expressions, we have to use default selectivities, which
+-- is why the estimates here are different from the pre-computed case above
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 = mod(a,100) AND 1 = mod(b::int,50)');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 1 AND mod(b::int,50) < 1');
+ estimated | actual
+-----------+--------
+ 556 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 > mod(a,100) AND 1 > mod(b::int,50)');
+ estimated | actual
+-----------+--------
+ 556 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 0 AND mod(b::int,50) <= 0');
+ estimated | actual
+-----------+--------
+ 556 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 0 >= mod(a,100) AND 0 >= mod(b::int,50)');
+ estimated | actual
+-----------+--------
+ 556 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1 AND mod(c,25) = 1');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND mod(b::int,50) < 1 AND mod(c,25) < 5');
+ estimated | actual
+-----------+--------
+ 185 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND 1 > mod(b::int,50) AND 5 > mod(c,25)');
+ estimated | actual
+-----------+--------
+ 185 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 4 AND mod(b::int,50) <= 0 AND mod(c,25) <= 4');
+ estimated | actual
+-----------+--------
+ 185 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 4 >= mod(a,100) AND 0 >= mod(b::int,50) AND 4 >= mod(c,25)');
+ estimated | actual
+-----------+--------
+ 185 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1');
+ estimated | actual
+-----------+--------
+ 75 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+ estimated | actual
+-----------+--------
+ 75 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52) AND mod(b::int,50) IN ( 1, 2)');
+ estimated | actual
+-----------+--------
+ 1 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52, NULL) AND mod(b::int,50) IN ( 1, 2, NULL)');
+ estimated | actual
+-----------+--------
+ 1 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2])');
+ estimated | actual
+-----------+--------
+ 1 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[NULL, 1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2, NULL])');
+ estimated | actual
+-----------+--------
+ 1 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, 2, 3]) AND mod(b::int,50) IN (1, 2, 3)');
+ estimated | actual
+-----------+--------
+ 53 | 150
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, NULL, 2, 3]) AND mod(b::int,50) IN (1, 2, NULL, 3)');
+ estimated | actual
+-----------+--------
+ 53 | 150
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+ estimated | actual
+-----------+--------
+ 391 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3, NULL])');
+ estimated | actual
+-----------+--------
+ 391 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, 3) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+ estimated | actual
+-----------+--------
+ 6 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, NULL, 3) AND mod(c,25) > ANY (ARRAY[1, 2, NULL, 3])');
+ estimated | actual
+-----------+--------
+ 6 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+ estimated | actual
+-----------+--------
+ 75 | 200
+(1 row)
+
+-- create statistics with expressions only (we create three separate stats, in order not to build more complex extended stats)
+CREATE STATISTICS mcv_lists_stats_1 ON (mod(a,100)) FROM mcv_lists;
+CREATE STATISTICS mcv_lists_stats_2 ON (mod(b::int,50)) FROM mcv_lists;
+CREATE STATISTICS mcv_lists_stats_3 ON (mod(c,25)) FROM mcv_lists;
+ANALYZE mcv_lists;
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 = mod(a,100) AND 1 = mod(b::int,50)');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 1 AND mod(b::int,50) < 1');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 > mod(a,100) AND 1 > mod(b::int,50)');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 0 AND mod(b::int,50) <= 0');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 0 >= mod(a,100) AND 0 >= mod(b::int,50)');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1 AND mod(c,25) = 1');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND mod(b::int,50) < 1 AND mod(c,25) < 5');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND 1 > mod(b::int,50) AND 5 > mod(c,25)');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 4 AND mod(b::int,50) <= 0 AND mod(c,25) <= 4');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 4 >= mod(a,100) AND 0 >= mod(b::int,50) AND 4 >= mod(c,25)');
+ estimated | actual
+-----------+--------
+ 1 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1');
+ estimated | actual
+-----------+--------
+ 343 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+ estimated | actual
+-----------+--------
+ 343 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52) AND mod(b::int,50) IN ( 1, 2)');
+ estimated | actual
+-----------+--------
+ 8 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52, NULL) AND mod(b::int,50) IN ( 1, 2, NULL)');
+ estimated | actual
+-----------+--------
+ 8 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2])');
+ estimated | actual
+-----------+--------
+ 8 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[NULL, 1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2, NULL])');
+ estimated | actual
+-----------+--------
+ 8 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, 2, 3]) AND mod(b::int,50) IN (1, 2, 3)');
+ estimated | actual
+-----------+--------
+ 26 | 150
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, NULL, 2, 3]) AND mod(b::int,50) IN (1, 2, NULL, 3)');
+ estimated | actual
+-----------+--------
+ 26 | 150
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+ estimated | actual
+-----------+--------
+ 10 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3, NULL])');
+ estimated | actual
+-----------+--------
+ 10 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, 3) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+ estimated | actual
+-----------+--------
+ 1 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, NULL, 3) AND mod(c,25) > ANY (ARRAY[1, 2, NULL, 3])');
+ estimated | actual
+-----------+--------
+ 1 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+ estimated | actual
+-----------+--------
+ 343 | 200
+(1 row)
+
+DROP STATISTICS mcv_lists_stats_1;
+DROP STATISTICS mcv_lists_stats_2;
+DROP STATISTICS mcv_lists_stats_3;
+-- create statistics with both MCV and expressions
+CREATE STATISTICS mcv_lists_stats (mcv) ON (mod(a,100)), (mod(b::int,50)), (mod(c,25)) FROM mcv_lists;
+ANALYZE mcv_lists;
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 = mod(a,100) AND 1 = mod(b::int,50)');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 1 AND mod(b::int,50) < 1');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 > mod(a,100) AND 1 > mod(b::int,50)');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 0 AND mod(b::int,50) <= 0');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 0 >= mod(a,100) AND 0 >= mod(b::int,50)');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1 AND mod(c,25) = 1');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND mod(b::int,50) < 1 AND mod(c,25) < 5');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND 1 > mod(b::int,50) AND 5 > mod(c,25)');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 4 AND mod(b::int,50) <= 0 AND mod(c,25) <= 4');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 4 >= mod(a,100) AND 0 >= mod(b::int,50) AND 4 >= mod(c,25)');
+ estimated | actual
+-----------+--------
+ 50 | 50
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1');
+ estimated | actual
+-----------+--------
+ 200 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+ estimated | actual
+-----------+--------
+ 200 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52) AND mod(b::int,50) IN ( 1, 2)');
+ estimated | actual
+-----------+--------
+ 200 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52, NULL) AND mod(b::int,50) IN ( 1, 2, NULL)');
+ estimated | actual
+-----------+--------
+ 200 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2])');
+ estimated | actual
+-----------+--------
+ 200 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[NULL, 1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2, NULL])');
+ estimated | actual
+-----------+--------
+ 200 | 200
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, 2, 3]) AND mod(b::int,50) IN (1, 2, 3)');
+ estimated | actual
+-----------+--------
+ 150 | 150
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, NULL, 2, 3]) AND mod(b::int,50) IN (1, 2, NULL, 3)');
+ estimated | actual
+-----------+--------
+ 150 | 150
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+ estimated | actual
+-----------+--------
+ 100 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3, NULL])');
+ estimated | actual
+-----------+--------
+ 100 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, 3) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+ estimated | actual
+-----------+--------
+ 100 | 100
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, NULL, 3) AND mod(c,25) > ANY (ARRAY[1, 2, NULL, 3])');
+ estimated | actual
+-----------+--------
+ 100 | 100
+(1 row)
+
+-- we can't use the statistic for OR clauses that are not fully covered (missing 'd' attribute)
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+ estimated | actual
+-----------+--------
+ 200 | 200
+(1 row)
+
-- 100 distinct combinations with NULL values, all in the MCV list
TRUNCATE mcv_lists;
DROP STATISTICS mcv_lists_stats;
@@ -1712,6 +2283,100 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR
(1 row)
DROP TABLE mcv_lists_multi;
+-- statistics on integer expressions
+CREATE TABLE expr_stats (a int, b int, c int);
+INSERT INTO expr_stats SELECT mod(i,10), mod(i,10), mod(i,10) FROM generate_series(1,10000) s(i);
+ANALYZE expr_stats;
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (2*a) = 0 AND (3*b) = 0');
+ estimated | actual
+-----------+--------
+ 1 | 1000
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (a+b) = 0 AND (a-b) = 0');
+ estimated | actual
+-----------+--------
+ 1 | 1000
+(1 row)
+
+CREATE STATISTICS expr_stats_1 (mcv) ON (a+b), (a-b), (2*a), (3*b) FROM expr_stats;
+ANALYZE expr_stats;
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (2*a) = 0 AND (3*b) = 0');
+ estimated | actual
+-----------+--------
+ 1000 | 1000
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (a+b) = 0 AND (a-b) = 0');
+ estimated | actual
+-----------+--------
+ 1000 | 1000
+(1 row)
+
+DROP STATISTICS expr_stats_1;
+DROP TABLE expr_stats;
+-- statistics on a mix columns and expressions
+CREATE TABLE expr_stats (a int, b int, c int);
+INSERT INTO expr_stats SELECT mod(i,10), mod(i,10), mod(i,10) FROM generate_series(1,10000) s(i);
+ANALYZE expr_stats;
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (2*a) = 0 AND (3*b) = 0');
+ estimated | actual
+-----------+--------
+ 1 | 1000
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 3 AND b = 3 AND (a-b) = 0');
+ estimated | actual
+-----------+--------
+ 1 | 1000
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND b = 1 AND (a-b) = 0');
+ estimated | actual
+-----------+--------
+ 1 | 0
+(1 row)
+
+CREATE STATISTICS expr_stats_1 (mcv) ON a, b, (2*a), (3*b), (a+b), (a-b) FROM expr_stats;
+ANALYZE expr_stats;
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (2*a) = 0 AND (3*b) = 0');
+ estimated | actual
+-----------+--------
+ 1000 | 1000
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 3 AND b = 3 AND (a-b) = 0');
+ estimated | actual
+-----------+--------
+ 1000 | 1000
+(1 row)
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND b = 1 AND (a-b) = 0');
+ estimated | actual
+-----------+--------
+ 1 | 0
+(1 row)
+
+DROP TABLE expr_stats;
+-- statistics on expressions with different data types
+CREATE TABLE expr_stats (a int, b name, c text);
+INSERT INTO expr_stats SELECT mod(i,10), md5(mod(i,10)::text), md5(mod(i,10)::text) FROM generate_series(1,10000) s(i);
+ANALYZE expr_stats;
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (b || c) <= ''z'' AND (c || b) >= ''0''');
+ estimated | actual
+-----------+--------
+ 111 | 1000
+(1 row)
+
+CREATE STATISTICS expr_stats_1 (mcv) ON a, b, (b || c), (c || b) FROM expr_stats;
+ANALYZE expr_stats;
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (b || c) <= ''z'' AND (c || b) >= ''0''');
+ estimated | actual
+-----------+--------
+ 1000 | 1000
+(1 row)
+
+DROP TABLE expr_stats;
-- Permission tests. Users should not be able to see specific data values in
-- the extended statistics, if they lack permission to see those values in
-- the underlying table.
diff --git a/src/test/regress/sql/create_table_like.sql b/src/test/regress/sql/create_table_like.sql
index 06b76f949d..4929d373a2 100644
--- a/src/test/regress/sql/create_table_like.sql
+++ b/src/test/regress/sql/create_table_like.sql
@@ -124,7 +124,9 @@ CREATE TABLE ctlt1 (a text CHECK (length(a) > 2) PRIMARY KEY, b text);
CREATE INDEX ctlt1_b_key ON ctlt1 (b);
CREATE INDEX ctlt1_fnidx ON ctlt1 ((a || b));
CREATE STATISTICS ctlt1_a_b_stat ON a,b FROM ctlt1;
+CREATE STATISTICS ctlt1_expr_stat ON (a || b) FROM ctlt1;
COMMENT ON STATISTICS ctlt1_a_b_stat IS 'ab stats';
+COMMENT ON STATISTICS ctlt1_expr_stat IS 'ab expr stats';
COMMENT ON COLUMN ctlt1.a IS 'A';
COMMENT ON COLUMN ctlt1.b IS 'B';
COMMENT ON CONSTRAINT ctlt1_a_check ON ctlt1 IS 't1_a_check';
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index cb08b478a4..ed294d73fa 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -28,16 +28,21 @@ end;
$$;
-- Verify failures
-CREATE TABLE ext_stats_test (x int, y int, z int);
+CREATE TABLE ext_stats_test (x text, y int, z int);
CREATE STATISTICS tst;
CREATE STATISTICS tst ON a, b;
CREATE STATISTICS tst FROM sometab;
CREATE STATISTICS tst ON a, b FROM nonexistent;
CREATE STATISTICS tst ON a, b FROM ext_stats_test;
CREATE STATISTICS tst ON x, x, y FROM ext_stats_test;
-CREATE STATISTICS tst ON x + y FROM ext_stats_test;
-CREATE STATISTICS tst ON (x, y) FROM ext_stats_test;
+CREATE STATISTICS tst ON x, x, y, x, x, y, x, x, y FROM ext_stats_test;
+CREATE STATISTICS tst ON x, x, y, x, x, (x || 'x'), (y + 1), (x || 'x'), (x || 'x'), (y + 1) FROM ext_stats_test;
+CREATE STATISTICS tst ON (x || 'x'), (x || 'x'), (y + 1), (x || 'x'), (x || 'x'), (y + 1), (x || 'x'), (x || 'x'), (y + 1) FROM ext_stats_test;
+CREATE STATISTICS tst ON (x || 'x'), (x || 'x'), y FROM ext_stats_test;
CREATE STATISTICS tst (unrecognized) ON x, y FROM ext_stats_test;
+-- incorrect expressions
+CREATE STATISTICS tst ON y + z FROM ext_stats_test; -- missing parentheses
+CREATE STATISTICS tst ON (x, y) FROM ext_stats_test; -- tuple expression
DROP TABLE ext_stats_test;
-- Ensure stats are dropped sanely, and test IF NOT EXISTS while at it
@@ -97,6 +102,36 @@ CREATE STATISTICS ab1_a_b_stats ON a, b FROM ab1;
ANALYZE ab1;
DROP TABLE ab1 CASCADE;
+-- basic test for statistics on expressions
+CREATE TABLE ab1 (a INTEGER, b INTEGER, c TIMESTAMP, d TIMESTAMPTZ);
+
+-- expression stats may be built on a single expression column
+CREATE STATISTICS ab1_exprstat_1 ON (a+b) FROM ab1;
+
+-- with a single expression, we only enable expression statistics
+CREATE STATISTICS ab1_exprstat_2 ON (a+b) FROM ab1;
+SELECT stxkind FROM pg_statistic_ext WHERE stxname = 'ab1_exprstat_2';
+
+-- adding anything to the expression builds all statistics kinds
+CREATE STATISTICS ab1_exprstat_3 ON (a+b), a FROM ab1;
+SELECT stxkind FROM pg_statistic_ext WHERE stxname = 'ab1_exprstat_3';
+
+-- expression must be immutable, but date_trunc on timestamptz is not
+CREATE STATISTICS ab1_exprstat_4 ON date_trunc('day', d) FROM ab1;
+
+-- but on timestamp it should work fine
+CREATE STATISTICS ab1_exprstat_5 ON date_trunc('day', c) FROM ab1;
+
+-- insert some data and run analyze, to test that these cases build properly
+INSERT INTO ab1
+SELECT
+ generate_series(1,10),
+ generate_series(1,10),
+ generate_series('2020-10-01'::timestamp, '2020-10-10'::timestamp, interval '1 day'),
+ generate_series('2020-10-01'::timestamptz, '2020-10-10'::timestamptz, interval '1 day');
+ANALYZE ab1;
+DROP TABLE ab1;
+
-- Verify supported object types for extended statistics
CREATE schema tststats;
@@ -272,6 +307,29 @@ SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE
TRUNCATE functional_dependencies;
DROP STATISTICS func_deps_stat;
+-- now do the same thing, but with expressions
+INSERT INTO functional_dependencies (a, b, c, filler1)
+ SELECT i, i, i, i FROM generate_series(1,5000) s(i);
+
+ANALYZE functional_dependencies;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1 AND mod(c, 7) = 1');
+
+-- create statistics
+CREATE STATISTICS func_deps_stat (dependencies) ON (mod(a,11)), (mod(b::int, 13)), (mod(c, 7)) FROM functional_dependencies;
+
+ANALYZE functional_dependencies;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE mod(a, 11) = 1 AND mod(b::int, 13) = 1 AND mod(c, 7) = 1');
+
+-- a => b, a => c, b => c
+TRUNCATE functional_dependencies;
+DROP STATISTICS func_deps_stat;
+
INSERT INTO functional_dependencies (a, b, c, filler1)
SELECT mod(i,100), mod(i,50), mod(i,25), i FROM generate_series(1,5000) s(i);
@@ -479,6 +537,28 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b =
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1'' AND c = 1');
+TRUNCATE mcv_lists;
+DROP STATISTICS mcv_lists_stats;
+
+-- random data (no MCV list), but with expression
+INSERT INTO mcv_lists (a, b, c, filler1)
+ SELECT i, i, i, i FROM generate_series(1,5000) s(i);
+
+ANALYZE mcv_lists;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,37) = 1 AND mod(b::int,41) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,37) = 1 AND mod(b::int,41) = 1 AND mod(c,47) = 1');
+
+-- create statistics
+CREATE STATISTICS mcv_lists_stats (mcv) ON (mod(a,37)), (mod(b::int,41)), (mod(c,47)) FROM mcv_lists;
+
+ANALYZE mcv_lists;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,37) = 1 AND mod(b::int,41) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,37) = 1 AND mod(b::int,41) = 1 AND mod(c,47) = 1');
+
-- 100 distinct combinations, all in the MCV list
TRUNCATE mcv_lists;
DROP STATISTICS mcv_lists_stats;
@@ -565,6 +645,8 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = '
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL');
+
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (1, 2, 51, 52) AND b IN ( ''1'', ''2'')');
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (1, 2, 51, 52, NULL) AND b IN ( ''1'', ''2'', NULL)');
@@ -602,6 +684,180 @@ ANALYZE mcv_lists;
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
+
+-- 100 distinct combinations, all in the MCV list, but with expressions
+TRUNCATE mcv_lists;
+DROP STATISTICS mcv_lists_stats;
+
+INSERT INTO mcv_lists (a, b, c, filler1)
+ SELECT i, i, i, i FROM generate_series(1,5000) s(i);
+
+ANALYZE mcv_lists;
+
+-- without any stats on the expressions, we have to use default selectivities, which
+-- is why the estimates here are different from the pre-computed case above
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 = mod(a,100) AND 1 = mod(b::int,50)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 1 AND mod(b::int,50) < 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 > mod(a,100) AND 1 > mod(b::int,50)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 0 AND mod(b::int,50) <= 0');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 0 >= mod(a,100) AND 0 >= mod(b::int,50)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1 AND mod(c,25) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND mod(b::int,50) < 1 AND mod(c,25) < 5');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND 1 > mod(b::int,50) AND 5 > mod(c,25)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 4 AND mod(b::int,50) <= 0 AND mod(c,25) <= 4');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 4 >= mod(a,100) AND 0 >= mod(b::int,50) AND 4 >= mod(c,25)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52) AND mod(b::int,50) IN ( 1, 2)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52, NULL) AND mod(b::int,50) IN ( 1, 2, NULL)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[NULL, 1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2, NULL])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, 2, 3]) AND mod(b::int,50) IN (1, 2, 3)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, NULL, 2, 3]) AND mod(b::int,50) IN (1, 2, NULL, 3)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3, NULL])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, 3) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, NULL, 3) AND mod(c,25) > ANY (ARRAY[1, 2, NULL, 3])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+
+-- create statistics with expressions only (we create three separate stats, in order not to build more complex extended stats)
+CREATE STATISTICS mcv_lists_stats_1 ON (mod(a,100)) FROM mcv_lists;
+CREATE STATISTICS mcv_lists_stats_2 ON (mod(b::int,50)) FROM mcv_lists;
+CREATE STATISTICS mcv_lists_stats_3 ON (mod(c,25)) FROM mcv_lists;
+
+ANALYZE mcv_lists;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 = mod(a,100) AND 1 = mod(b::int,50)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 1 AND mod(b::int,50) < 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 > mod(a,100) AND 1 > mod(b::int,50)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 0 AND mod(b::int,50) <= 0');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 0 >= mod(a,100) AND 0 >= mod(b::int,50)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1 AND mod(c,25) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND mod(b::int,50) < 1 AND mod(c,25) < 5');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND 1 > mod(b::int,50) AND 5 > mod(c,25)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 4 AND mod(b::int,50) <= 0 AND mod(c,25) <= 4');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 4 >= mod(a,100) AND 0 >= mod(b::int,50) AND 4 >= mod(c,25)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52) AND mod(b::int,50) IN ( 1, 2)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52, NULL) AND mod(b::int,50) IN ( 1, 2, NULL)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[NULL, 1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2, NULL])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, 2, 3]) AND mod(b::int,50) IN (1, 2, 3)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, NULL, 2, 3]) AND mod(b::int,50) IN (1, 2, NULL, 3)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3, NULL])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, 3) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, NULL, 3) AND mod(c,25) > ANY (ARRAY[1, 2, NULL, 3])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+
+DROP STATISTICS mcv_lists_stats_1;
+DROP STATISTICS mcv_lists_stats_2;
+DROP STATISTICS mcv_lists_stats_3;
+
+-- create statistics with both MCV and expressions
+CREATE STATISTICS mcv_lists_stats (mcv) ON (mod(a,100)), (mod(b::int,50)), (mod(c,25)) FROM mcv_lists;
+
+ANALYZE mcv_lists;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 = mod(a,100) AND 1 = mod(b::int,50)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 1 AND mod(b::int,50) < 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 1 > mod(a,100) AND 1 > mod(b::int,50)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 0 AND mod(b::int,50) <= 0');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 0 >= mod(a,100) AND 0 >= mod(b::int,50)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 AND mod(b::int,50) = 1 AND mod(c,25) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND mod(b::int,50) < 1 AND mod(c,25) < 5');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < 5 AND 1 > mod(b::int,50) AND 5 > mod(c,25)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= 4 AND mod(b::int,50) <= 0 AND mod(c,25) <= 4');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 4 >= mod(a,100) AND 0 >= mod(b::int,50) AND 4 >= mod(c,25)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52) AND mod(b::int,50) IN ( 1, 2)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) IN (1, 2, 51, 52, NULL) AND mod(b::int,50) IN ( 1, 2, NULL)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = ANY (ARRAY[NULL, 1, 2, 51, 52]) AND mod(b::int,50) = ANY (ARRAY[1, 2, NULL])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, 2, 3]) AND mod(b::int,50) IN (1, 2, 3)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) <= ANY (ARRAY[1, NULL, 2, 3]) AND mod(b::int,50) IN (1, 2, NULL, 3)');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(c,25) > ANY (ARRAY[1, 2, 3, NULL])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, 3) AND mod(c,25) > ANY (ARRAY[1, 2, 3])');
+
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) < ALL (ARRAY[4, 5]) AND mod(b::int,50) IN (1, 2, NULL, 3) AND mod(c,25) > ANY (ARRAY[1, 2, NULL, 3])');
+
+-- we can't use the statistic for OR clauses that are not fully covered (missing 'd' attribute)
+SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE mod(a,100) = 1 OR mod(b::int,50) = 1 OR mod(c,25) = 1 OR d IS NOT NULL');
+
-- 100 distinct combinations with NULL values, all in the MCV list
TRUNCATE mcv_lists;
DROP STATISTICS mcv_lists_stats;
@@ -894,6 +1150,57 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR
DROP TABLE mcv_lists_multi;
+
+-- statistics on integer expressions
+CREATE TABLE expr_stats (a int, b int, c int);
+INSERT INTO expr_stats SELECT mod(i,10), mod(i,10), mod(i,10) FROM generate_series(1,10000) s(i);
+ANALYZE expr_stats;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (2*a) = 0 AND (3*b) = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (a+b) = 0 AND (a-b) = 0');
+
+CREATE STATISTICS expr_stats_1 (mcv) ON (a+b), (a-b), (2*a), (3*b) FROM expr_stats;
+ANALYZE expr_stats;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (2*a) = 0 AND (3*b) = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE (a+b) = 0 AND (a-b) = 0');
+
+DROP STATISTICS expr_stats_1;
+DROP TABLE expr_stats;
+
+-- statistics on a mix columns and expressions
+CREATE TABLE expr_stats (a int, b int, c int);
+INSERT INTO expr_stats SELECT mod(i,10), mod(i,10), mod(i,10) FROM generate_series(1,10000) s(i);
+ANALYZE expr_stats;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (2*a) = 0 AND (3*b) = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 3 AND b = 3 AND (a-b) = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND b = 1 AND (a-b) = 0');
+
+CREATE STATISTICS expr_stats_1 (mcv) ON a, b, (2*a), (3*b), (a+b), (a-b) FROM expr_stats;
+ANALYZE expr_stats;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (2*a) = 0 AND (3*b) = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 3 AND b = 3 AND (a-b) = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND b = 1 AND (a-b) = 0');
+
+DROP TABLE expr_stats;
+
+-- statistics on expressions with different data types
+CREATE TABLE expr_stats (a int, b name, c text);
+INSERT INTO expr_stats SELECT mod(i,10), md5(mod(i,10)::text), md5(mod(i,10)::text) FROM generate_series(1,10000) s(i);
+ANALYZE expr_stats;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (b || c) <= ''z'' AND (c || b) >= ''0''');
+
+CREATE STATISTICS expr_stats_1 (mcv) ON a, b, (b || c), (c || b) FROM expr_stats;
+ANALYZE expr_stats;
+
+SELECT * FROM check_estimated_rows('SELECT * FROM expr_stats WHERE a = 0 AND (b || c) <= ''z'' AND (c || b) >= ''0''');
+
+DROP TABLE expr_stats;
+
+
-- Permission tests. Users should not be able to see specific data values in
-- the extended statistics, if they lack permission to see those values in
-- the underlying table.
--
2.26.2
--------------8FD28E9B65A94BB176003065--
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Subject: Re: [PATCH 3/3] Extended statistics on expressions
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